Update free-books.md

adamgomes · web-flow · commit 63585c3601d9 · 2016-10-03T08:14:42.000-04:00
diff --git a/extras/free-books.md b/extras/free-books.md
@@ -48,6 +48,10 @@ Name | Author(s)
 
 ### Math (Discrete Math)
 
+Name | Author(s)
+:-- | :--:
+[Applied Discrete Structures](http://faculty.uml.edu/klevasseur/ads2/) | Alan Doerr, Ken Levasseur
+
 ### Algorithms
 
 ### Programming Paradigms
