1. Hebb DO, The Organization of Behavior, John Wiley, New York, NY, 1949.
2. Watkins CJCH (1989). Learning from Delayed Rewards. PhD Thesis, King's College, http://www.cs.rhul.ac.uk/home/chrisw/new_thesis.pdf.
3. Hull CL (1943). Principles of behavior. New York: Appleton-Century.
4. Barto, Sutton, Anderson, http://webdocs.cs.ualberta.ca/∼sutton/book/ebook/the-book.html.
5. Schultz W (2007). Predictive reward signal of dopamine neurons. Neurophysiology, 80, 1-27.