1. Ackerman D. (1999). Deep play. New York: Random House. Ackerman D. (1999). Deep play. New York: Random House.
2. Keller M. (2016). Freecell faq. http://solitairelaboratory.com/fcfaq.html. (Accessed: 2016-09-30) Keller M. (2016). Freecell faq. http://solitairelaboratory.com/fcfaq.html. (Accessed: 2016-09-30)