APA (7th ed.) Citation
Mischel, W. (2015). <The> Marshmallow Test: Understanding Self-Control and How to Master It. Corgi Books.
Chicago Style (17th ed.) Citation
Mischel, Walter. <The> Marshmallow Test: Understanding Self-Control and How to Master It. London: Corgi Books, 2015.
MLA (9th ed.) Citation
Mischel, Walter. <The> Marshmallow Test: Understanding Self-Control and How to Master It. Corgi Books, 2015.
Warning: These citations may not always be 100% accurate.