Motivation and emotion/Book/2020/Compassion focused therapy

Compassion focused therapy:
What is CFT and how can it be applied?

Overview edit

 
Image 1. Compassion focused therapy draws from Buddhist Psychology.

The word Compassion means ‘to suffer with’. Compassion can be defined as “the emotion one experiences when feeling concern for another's suffering and desiring to enhance that individual's welfare” (Klimecki, 2013). Compassion can be someone or some act that shows kindness and empathy to others. When this emotion occurs you might feel a sense of warmth, empathy, caregiving or even a desire to help a suffering person in some way.

This book chapter explains compassion focused therapy, so we can understand and improve our emotional lives using psychological science. This chapter begins with an overview of the key concepts of compassion. The theoretical framework of compassion focused therapy are then explored. The chapter ends with how we can incorporate compassion techniques from CFT, leading into what we need to explore in the future.

Focus questions:

  • What is Compassion?
  • How does Compassion influence emotion?
  • What is Compassion focused therapy?

What is Compassion? edit

"Love and compassion are necessities not luxuries, without them humanity cannot survive". – Dalai Lama

[missing something?]

Characteristics of Compassion edit

 
Image 2. People appreciate and never forget a helping hand, especially when times are tough. This is a true sign of compassion.

There are many different dimensions of compassion. In compassion focused therapy, compassion is interpreted in terms of specific skills and attributes (Gilbert, 2009). Compassionate mind training (CMT) is central to compassion focused therapy (CFT). The therapist instils and encourages a framework of compassion in the client, to replace and shift the blame and guilt off oneself, and is encouraged to develop an internal compassionate relationship with themselves.[factual?]

Compassion as an emotion. edit

What does compassion look like as an emotion?

Compassion, as a social mentality, can ‘flow’ in three directions. First, there is the compassion we can feel for another or others; then, there is the compassion we can feel coming from others to ourselves, and then there is the compassion we can direct to ourselves (self-compassion). Each of these are focus' in CFT (Gilbert, 2014).

According to Neff (2003) [grammar?] self-compassion is conceptualised and entails three components; self-kindness, shared humanity and mindful acceptance. Self-kindness requires being emotionally warm and non-judgemental towards oneself in times of difficulty; general empathy requires the understanding that the challenges of life are part of human experience; and mindfulness entails being able to understand and acknowledge painful thoughts and feelings (Mackintosh, 2009). A more in depth explanation can be found in the compassion and empathy book chapter.

Studies have indicated that we can learn to be kinder to ourselves, and in particular adopt a caring voice for our inner critique, to ease difficult emotions and develop strengths and motivations[factual?]. Individuals who score higher in self-compassion have been shown to experience a heightened amount of positive emotions, more confidence, satisfying relationships and a higher quality of life (Bloomfield, 2015).

How compassionate are you? A way to see how compassionate you are is to take a quick quiz.

Compassion as skill. edit

Compassion can be deemed a skill that an individual can train in, with swelling evidence that those who reflect and focus on practising compassion, can positively influence their neurophysiological and immune systems (Gilbert, 2009). Individuals can be taught to engage mindfully with a range of therapeutic interventions that focus on thoughts feelings and behaviours. The skills involved in compassion are the emotions of warmth, kindness and support. These emotions are multimodal and common to many other psychotherapies (Gilbert, 2009). It is really important and useful to teach clients to use these skills (emotions) on themselves. A study identified that when individuals were asked how they attempt to help themselves, highly shameful patients explained that when trying to change their thoughts and behaviours, they would use a cold bullying or aggressive inner voice. Therapists should explore whether clients are trying to force or bully themselves into change, in comparison to being supportive and encouraging of their attempts to do so (Gilbert, 2009).

How do we find Compassion. edit

Self-compassion entails being warm and understanding toward ourselves when we suffer, fail, or feel feel inadequate rather than ignoring our pain or flagellating ourselves with self-criticism. Self-compassionate people recognize that being imperfect, failing, and experiencing life difficulties is inevitable, so they tend to be gentle with themselves when confronted with painful experiences rather than getting angry when life falls short of set ideals.


Example: Compassionate Self

"I had a really tough time period in my life where I feel like I fell into darkness. The voice in my head had nothing but awful things to say about myself. It really affected my self-esteem, I was always in a depressed mood and had high levels of anxiety. This then made me fall behind in university and work. I felt it was all my fault and had high levels of shame. I knew I needed to be more understanding of myself needed to show myself more compassion just as I show other people. It wasn't until I told myself I wanted to feel happy again that I started self-compassion, meditating, trying relaxation exercises and compassionate letter writing/gratitude journaling. This completely changed my life" (Author).

What is Compassion focused therapy? edit

 
Image 4. The three aspects of therapeutic engagement. (Gilbert, 2009)

Dr. Paul Gilbert, an English psychologist founded CFT and concluded that kindness (both self and other focused) could be the secret to relieving intrusive feelings of guilt and self-criticism (Gilbert, 2009). Compassion focused therapy is an integrative evidence based, psychotherapy model. CFT evolved from cognitive behavioural therapy techniques (CBT) that included the concept of self-compassion. Over time various frameworks such as evolutionary, social, developmental, affective neuroscience and Buddhist psychology theories were integrated in compassion focused therapy (Gilbert, 2009). CFT processes are also inspired by the evolutionary and psycho-education models, and seek to depersonalise and de-shame by helping the individual understand how their brain regulates emotion (Klimecki, 2013). 

CFT was initially developed for individuals with long-term emotional issues, often associated with high levels of guilt, shame, self-criticism, anxiety, depression, eating disorders, anger, self-injury and psychosis, while also having increasing evidence for a variety of clinical disorders (Frostadottir, 2019). It has been shown that practising compassion has powerful effects on physiological, psychological and social processes, particularly in the regulation of threat-focused emotional experiences and the development of a caring orientation[factual?]. Compassion focused therapy focuses on the skills and attributes of compassionate characteristics as depicted in Image 2. A number of self-soothing techniques are also used in CFT, [grammar?] this is designed to develop empathy, compassion, love and kindness towards oneself and others. A key notion is that compassion focused therapy promotes and encourages is understanding, safety, warmth and comfort which will alleviate and reduce anxiety and depression (Bloomfield, 2015). CFT’s purpose is meant to help promote mental and emotional recovery by encouraging individuals to be more compassionate towards themselves and others.

Compassion focused therapy can be helpful to those who find it hard to understand, feel or express compassion towards themselves and others. Experiencing or demonstrating compassion may be daunting to those individuals. CFT therapy can be a safe place to uncover the causes behind this difficulty and discover methods of positive change. CFT can also be effective and successful in helping individuals handle distressing thoughts, behaviours and feelings. CFT can be especially helpful when coping with self attack related feelings (Braehler, 2013). Three aspects of therapeutic engagement have been displayed in image 4. This can give us an indication about what happens in a clinical setting with a therapist.[factual?]

Table 1.

What sets Compassion focused therapy apart from [what?] others.

Features
The philosophies of the Western and Eastern Compassion focused therapy comes from a number of frameworks. [grammar?] these include evolutionary, biology, neuroscience and Buddhist psychology. Most of these therapies are firmly based in on one discipline or philosophy.
CFT takes a view of the mind that is interactions [grammar?] and compensatory (Gilbert, 2010). This is the perception that the mind is structured in a way that some mentalities can be ignored while others thrive or take control. Negative, harmful or maladaptive relations can be created and have major effects on mentality. Changing ones[grammar?] mindset can either have positive or negative impacts on others also.
The idea of social mentalities (Gilbert, 2010)

Gilbert identified a set of “social mentalities” that enable them to seek out and form certain types of relationships (e.g., sexual, tribal, dominant-subordinate, caring of-cared for)

Another one of compassion focused therapies main traits is the use of mind training (CMT) to help individuals develop and work with their feelings of inner warmth, safety and security (Gilbert, 2009). Being compassionate towards the self as well as others is an emotional reaction that many consider to be an important element of well-being. CFT’s progress can often be beneficial to improved mental and emotional health (Leaviss, 2015)[Provide more detail].

Therapists applying compassion focused therapy need to be concerned about the perspectives of the client, and provide empathy, validation and warmth. Such behaviours and attitudes can help clients face painful emotions to change, recognise and understand the impulses and desires that underlie these emotions. CFT therapists can work in calming ways to regulate the threat system described further down the chapter. We are all born with each system in motion, ready in place to go, however our environmental world influences affects whether we develop, use and maintain the non-survival based systems.[factual?]


Example

The feeling of only ever having compassion for other people and never having any for myself. Suddenly realizing that it’s always been there, just that I never knew how to use it towards myself. It was such a beautiful, calming feeling to know it was OK to feel like this towards myself without feeling guilty or bad about it. Being able to draw on this when I was frightened and confused, to calm myself down and to put things in perspective and say to myself ‘IT’S OK TO FEEL LIKE THIS’ (Gilbert, 2010).

How does Compassion focused therapy influence emotion? edit

Identifying the influences of emotions can help individuals access their impulses and desires that underlie each emotion. Emotions According to Maslow (1943) are in our basic needs and desires; so experiencing and identifying emotions will help individuals change and improve individuals problematic emotional patterns and encourage them to handle their emotions in a healthier way (McLeod, 2020).

 
Image 5. This is Maslow's hierarchy of needs [grammar?] a perfect representation of our basic needs desires and wants.

Emotions are separated into four types, these are; adaptive primary emotions, maladaptive primary emotions, secondary emotions, and instrumental emotions[factual?]. These are differentiated so therapists can understand a clients[grammar?] emotions and put their thoughts into words (Asano, 2019). Adaptive primary and maladaptive primary emotions are responses to a stimulus or the environment and are natural reactions for survival in dangerous situations. These emotions are represented as fear, anger, anxiety, and help to produce a calm response to the situation. Maladaptive primary emotions are acquired and learned from past events or unresolved grief and can include guilt, shame, feeling worthless, unloved, and sadness. These emotions can arise from loneliness, deprivation and anxiety. The main core emotions of maladaptive primary emotions are very dark, these emotions can be difficult to suppress, regulate and manage. Individuals tend to dwell over these maladaptive emotions as a result (Asano, 2019).

The concept of multiple selves is used by CFT practitioners to understand and describe conflicting emotions such as maladaptive primary emotions. The multiple self is based on the idea and assumption that there are many versions of the self, meaning that an individual comprises of parts that are angry, anxious, fearful, disgusted, joyful etc. The attributes refer to one's sense of self and perception. Individuals can experience a confused state of maladaptive primary emotions based on this assumption, in which they have not experienced each emotion and are instead controlled by mixed emotional pain (Asano, 2019). Therefore, separating and distinguishing emotions from emotional pain can allow individuals to overcome and address the the underlying desires and emotions. This in turn aids individuals to cope in a healthier manner. When applying CFT, the therapist allows the client to integrate their needs and desires while demonstrating empathy and compassion, and determines how to react to the problems and pain using the individuals compassionate self[factual?].

While influencing emotion in a numerous amount of ways, a study by Klimecki et al., 2013, also revealed that CFT increases and enhances the efficacy of the immune system. CFT increases lower blood pressure and cortisol release, reduce paranoia, and negative emotions associated with personality disorders, while also improving general psychological well-being (Klimecki, 2013).

Theoretical Framework edit

Example: CFT and eating disorders.

To understand how CFT can support individuals dealing with eating disorders, and self-esteem issues, Researchers Stanley Steindl, Kiera Buchanan, Kenneth Goss, and Steven Allan (2017) ventured into the literature on CFT and eating disorders. They found that higher self-criticism, guilt, shame and lower self-compassion are correlated. They found that for those dealing with eating disorders, CFT can be successfully applied to improve their self-confidence and self-acceptance (Steindl et al., 2017).

The Compassionate Mind edit

 
Image 6. Affect regulation systems. Gilbert (2005)

Compassion focused therapy combines elements of attachment and evolutionary theories, with the latter focusing on the affiliative system.

Paul Gilbert's evolutionary model proposes that humans beings switch between three systems to manage their emotions. Each system is associated with different brain regions and different brain chemistry, Distress is caused by an imbalance between the systems, often associated with under-developed of the soothing system (Bloomfield, 2015).

Affect regulations systems (Gilbert, 2005[missing from references])
The Threat and protection system.
The drive, resource seeking, incentive focused and excitement system.
The soothing/affiliative and safeness system.

This model displays the actions that individuals may experience when regulating emotions in a situation. The threat-protection system signals and directs attention to traits that an individual may perceive as threatening, which stimulates the body into action. When we experience emotions such as anger, fear, disgust and other emotions that usually evoke hardship, the threat-protection system is activated. These emotions lead us to act in certain ways because of the emotions played in our ancestors, these emotions trigger us to either fight, flight or flee (Dore, 2016). We are activated to respond almost immediately by extreme blasts of physical and emotional stimuli in order to protect ourselves from any danger we have perceived, whether actual or imaginary (Dore, 2016). Unfortunately, our ability to behave efficiently is reduced when our threat-protection system is triggered. Thousands of years of evolution reinforced this threat-protection system, and plays a big role in our own survival, ultimately this reinforcement has magnified the strength of these emotions (Dore, 2016).

Although important, survival was not the only motivation for our ancestors. They also had to reproduce and thrive. The Drive is a resource seeking, incentive focused and excitement system, developed to hunt animals to find food, shelter, and sexual partners. This characteristic is related to motivating, accomplishing, needing, avoiding rejection and consuming activities. The drive system is triggered as we experience emotions like excitement, anticipation, lust, motivation and the drive to do something more than defend ourselves. These are the emotions that drive us to go to work, purchase a home, meet a partner and engage in social events. Dopamine affects emotions associated with the drive system, because whether this system is too active or in equilibrium, the things that drive us will become objects in attachment, craving and addiction (Dore, 2016).

The soothing/affiliative and safeness system is associated to social connection and is different to the other two systems. Affection and kindness are traits that are responsible for decreasing and reducing threat responses to feared stimuli. When we aren’t exposed to threats or goals to pursue, we are in a resting state in which we feel calm, safe and at ease. When we feel compassion, love and affection this system is activated (Dore, 2016). This response also activates feelings of safety, bonding and trust. When distraught, being in company of compassion creates a sense of security, while increasing the feelings of safeness. Compassion relieves the threat-response system in response to danger. The goal of compassion focused therapy is to balance the three regulation structures by building the soothing/affiliative and safeness system. When in a clinical setting, individuals are taught how each of the three processes influences one another. Once the client stops condemning and blaming themselves for their symptoms, thinking and feelings, they are freer to progress towards taking responsibility and learning to cope (klimecki, 2013). This mechanism is also correlated with acts that are calming, soothing and stress-reducing either though the self or through others. Oxytocin and endorphins are chemicals releases as a result of the soothing system involved with these kind of interactions, and have been found to provide health benefits and advantages such as improved immune and digestive function (Dore, 2016).

In a clinical setting, it is crucial to note that when trying to communicate with individuals [missing something?] may trigger the threat response system rather than the safeness system, for many individuals who have had less than stable attachment experiences (Dore, 2016).

Compassion is one form of activating the safeness system while disabling the threat and drive systems. By helping and guiding individuals with compassion focused therapy, we will continue to normalise and de-stigmatise the process of suffering, pain and emotional difficulty. CFT will also help individuals understand the vulnerabilities of their mind. Guiding these individuals to sort their emotional feelings into one of the three systems when that feel triggered is a smart way to develop mindful awareness and encourage an observational perspective (Dore, 2016).

Have you been paying attention?
Test yourself!

1 Is oxytocin released when the soothing and caring system is activated?.

YES.
NO.

2 CFT’s purpose is meant to help promote mental and emotional recovery by encouraging individuals to be more compassionate towards themselves and others.

FALSE.
TRUE.

Techniques and exercises in CFT edit

Paul Gilbert explored a way in which we can train our brain and teach our minds to feel comforted by a friendly compassionate voice, as well as a series of techniques such as mindfulness exercises and visualisations to better control challenging emotions (Bloomfield, 2015). Compassion can be trained and it is cultivated by mental exercises such as meditation and other exercises seen in Table 2. (Reeve, 2014).

In CFT the aim is to take care of our own well-being, needs and distress and give ourselves conform and understanding when we struggle rather than punishing ourselves. Mindfulness approaches vary, although the key is the use of comforting inner thought. We are able to develop a compassionate voice which is calm, peaceful, encouraging, uplifting and motivating (Bloomfield, 2015).

Table 2.

Overview of the CFT exercises (adapted from Gilbert, 2010).

Exercise Description
Soothing rhythm breathing This exercise involves focusing on the breath, finding a soothing rhythm, paying attention to the the link between breathing and physiology. This exercise forms the basis of many of the other imagery exercises. Try it out (Youtube)
Mindfulness This involves teaching people to pay attention to the present moment, and learning to observe their internal and external worlds. This exercise is to increase awareness of the mind, learn to notice when it has wandered and return to the present moment. Watch a TED talk.
Safe place imagery This exercise involves generating an image of somewhere the person feels safe, calm and soothed. This introduces people to imagery exercises and the idea that it is less about generating a clear image and more about an emotional connection to the image.
colour imagery This exercise involves imagining a colour that the person associates with warmth, kindness and compassion, and trying to imagine that the colour has a motivation and wants to help the person. The purpose is to practice feeling cared for, with a colour often being less threatening than imagining a person.
self imagery This exercise involves imagining the self who has three core qualities of wisdom, strength and commitment to care, even if the individual feels that they do not have these qualities. This sense and version of oneself is then used as the basis for other exercises, including imagining being compassionate towards others and towards the self.
letter writing This exercise involves writing a letter to the self, from a compassionate perspective, to help people reflect empathically and develop self‐compassion.
behaviour People are encouraged to do things for themselves and others which will help them to develop and flourish; this is not necessarily about doing ‘nice’ things, indeed, sometimes it involves confronting and working with difficult situations, emotions and memories.
thinking This involves learning how to generate alternative, compassionate ways of thinking (e.g. mentalizing) in response to threat‐focused and/or self‐critical thoughts

The limitations of Compassion focused therapy edit

Many individuals cannot tune into their soothing and social safeness system that underlies compassion[factual?]. [grammar?]being able to identify common fears, blocks and resistances is what underpins compassion focused therapy. Some clients have very bad views about compassion[factual?]. Being able to have self-awareness and become forgiving and compassionate to others also needs to be addressed when beginning compassion focused therapy. Attachment theories say that the attachment system can be reactivated by signs of compassion and and kindness from another individuals (especially a therapist)[factual?]. Complex and unresolved memories may arise from the attachment system especially for high-shame and self-critical individuals[factual?]. Some Individuals are overwhelmed and even dissociate from the pain of their grief (Goss, 2014). The therapist applying CFT should help to validate, normalise, contain and work with the individuals[grammar?] feelings[factual?]. CFT imagery exercises can be physiologically stressful for some individuals[factual?]. Therapists need to be able to apply evolutionary functional analysis to emotions. CFT therapists need to be concerned about the perspectives of the client, and provide empathy, validation and warmth[factual?]. Such behaviours and attitudes can help clients face painful emotions to change, recognise and understand the impulses and desires that underlie these emotions. CFT therapists can work in a calming way to regulate the threat system. This can lead into compassion fatigue or burnout which is a period of fatigue after physiological, mental and or physical stress that has been endured (Goss, 2014).

Lack of standardisation in the current research[grammar?]. Further research will reduce existing methodological limitations (Craig, 2020). Future trials should ensure that CFT interventions comprehensively follow the core principles of the therapy’s underlying principles in order to appropriately assess its efficacy. Further research also needs to focus on individual CFT sessions and the longer-term impact of the therapy (Craig, 2020).

Conclusion edit

“The things that have happened to you in your life are not your fault, but it is your responsibility to alleviate your suffering.” (Ackerman, 2020)

Compassion focused therapy is grounded in evolutionary approaches to the emergence of the human mind and the role of affiliation that regulates threat processes and highlights the importance of caring, helping, sharing and feeling valued (Gilbert, 2014).  It is called compassion focused therapy and not compassion therapy, because it focuses on the development of skills and brain systems that play a significant role in threat regulation, prosocial behaviour and well-being (improving prosocial behaviour is forgotten occasionally as a potential goal and possible treatment)(Gilbert, 2015).

According to Courtney E. Ackerman, a positive psychologist, CFT's aim is to help individuals grow and improve their caregiving system, which allows them to feel at ease and comfortable with their thoughts in their own head. Strength, warmth, empathy , kindness and courage can be enabled by the caregiving system, as these characteristics are linked to compassion (Ackerman, 2020). Three major components are related to compassion, these include;

  1. learning about human nature
  2. learning skills to develop the caregiving system
  3. practicing activating the caregiving system and using it in ones daily life (Ackerman, 2020).

A solution for self-critical judgement is to cultivate techniques that channel compassion. Although suffering cannot be stopped, reacting to suffering in a positive way encourages healing and impacts on well-being, family, professional and social level by adopting the role of being 'kinder to myself' (Frostadottir, 2019).

See also edit

References edit

Ackerman, C.E. (2020). 16 Compassion Focused Therapy Training Exercises and Worksheets. PositivePsychology.com. https://positivepsychology.com/compassion-focused-therapy-training-exercises-worksheets/.

An Introduction to Compassion-Focused Therapy. Compassionate Mind Australia. from https://www.compassionatemind.org.au/new-events/2018/10/24/an-introduction-to-compassion-focused-therapy

Asano, K. (2019). Emotion processing and the role of compassion in psychotherapy from the perspective of multiple selves and the compassionate self. Case Reports in Psychiatry. https://doi.org/10.1155/2019/7214752

Beaumont, E. A. (2017). Being kinder to myself: using compassion focused therapy and compassionate mind training to help individuals in the helping professions cultivate compassion (Doctoral dissertation, University of Salford).

Bloomfield, M. (2015). Compassion-Focused Therapy to reduce stress, anxiety and depression (CFT). bloomfieldpsychology. https://www.bloomfieldpsychology.com.au/blog/compassion-focused-therapy-dissolve-shame-and-self-hate.

Braehler, C., Gumley, A., Harper, J., Wallace, S., Norrie, J., & Gilbert, P. (2013). Exploring change processes in compassion focused therapy in psychosis: Results of a feasibility randomized controlled trial. British Journal of Clinical Psychology, 52(2), 199-214. https://doi.org/10.1111/bjc.12009

Craig, C., Hiskey, S., & Spector, A. (2020). Compassion Focused Therapy: a systematic review of its effectiveness and acceptability in clinical populations. Expert Review of Neurotherapeutics, 20(4), 385-400. https://doi.org/10.1080/14737175.2020.1746184

Dore, J. (2016). The Compassion-Focused Therapy Model of Emotions. Psych Central. Retrieved on October 10, 2020, from https://pro.psychcentral.com/the-compassion-focused-therapy-model-of-emotions/

Frostadottir, A. D., & Dorjee, D. (2019). Effects of mindfulness based cognitive therapy (MBCT) and compassion focused therapy (CFT) on symptom change, mindfulness, self-compassion, and rumination in clients with depression, anxiety, and stress. Frontiers in Psychology,10, 1099. https://doi.org/10.3389/fpsyg.2019.01099

Gilbert, P. (2009). Introducing compassion-focused therapy. Advances in psychiatric treatment, 15(3), 199. doi: 10.1192/apt.bp.107.005264

Gilbert, P. (2010). Compassion focused therapy: The CBT distinctive features series. New York, NY: Routledge.

Gilbert, P. (2014). The origins and nature of compassion focused therapy. British Journal of Clinical Psychology, 53(1), 6-41. https://doi.org/10.1111/bjc.12043

Goss, K. & Allan, S. (2014). The development and application of compassion-focused therapy for eating disorders. British Journal of Clinical Psychology, 53, 62-77. https://doi.org/10.1111/bjc.12039

Klimecki, O. M., Leiberg, S., Lamm, C., & Singer, T. (2013). Functional neural plasticity and associated changes in positive affect after compassion training. Cerebral cortex, 23(7), 1552-1561. https://doi.org/10.1093/cercor/bhs142

Mackintosh, K., Power, K., Schwannauer, M., & Chan, S. W. (2018). The relationships between self-compassion, attachment and interpersonal problems in clinical patients with mixed anxiety and depression and emotional distress. Mindfulness, 9(3), 961-971. https://doi.org/10.1007/s12671-017-0835-6

McLeod, S. (2020). Maslow’s Hierarchy of Needs. SimplyPsychology. https://www.simplypsychology.org/maslow.html.

Leaviss, J., & Uttley, L. (2015). Psychotherapeutic benefits of compassion-focused therapy: An early systematic review. Psychological medicine, 45(5), 927-945. https://doi.org/10.1017/S0033291714002141

Steindl, S. R., Buchanan, K., Goss, K., & Allan, S. (2017). Compassion focused therapy for eating disorders: A qualitative review and recommendations for further applications. Clinical Psychologist 21, 62-73. doi:10.1111/cp.12126

Reeve, J. (2014). Understanding motivation and emotion. John Wiley & Sons.

External links edit