* Grinstead, CM and Snell, JL (1997), "Introduction to Probability (2nd edition)", American Mathematical Society (free pdf available) [http://www.dartmouth.edu/~chance/teaching_aids/books_articles/probability_book/book.html].
* Charles M. Grinstead and J. Laurie Snell (1997), «Introduction to Probability (2nd edition)», American Mathematical Society (free pdf available [http://www.dartmouth.edu/~chance/teaching_aids/books_articles/probability_book/book.html].