@@ -372,6 +372,7 @@ Original Source: [Free Programming books](http://stackoverflow.com/revisions/392
*[Elementary Differential Equations](http://ramanujan.math.trinity.edu/wtrench/texts/TRENCH_DIFF_EQNS_I.PDF) - William F. Trench
*[Essentials of Metaheuristics](http://cs.gmu.edu/~sean/book/metaheuristics/) by Sean Luke
*[Introduction to Probability](http://www.dartmouth.edu/~chance/teaching_aids/books_articles/probability_book/book.html) - Charles M. Grinstead and J. Laurie Snell
*[Introduction to Probability and Statistics Spring 2014](http://ocw.mit.edu/courses/mathematics/18-05-introduction-to-probability-and-statistics-spring-2014/)
*[Introduction to Statistical Thought](http://www.math.umass.edu/~lavine/Book/book.html) - Michael Lavine
