Fix link

free-programming-books.md

@@ -196,7 +196,7 @@
 * [Foundations of Computer Science](http://infolab.stanford.edu/~ullman/focs.html) - Al Aho and Jeff Ullman
 * [A Field Guide To Genetic Programming](http://dces.essex.ac.uk/staff/rpoli/gp-field-guide/toc.html)
 * [The Art of Computer Programming](http://www.cs.utsa.edu/~wagner/knuth/) (fascicles, mostly volume 4) - Donald Knuth
-* [Programming Pearls](http://cs.bell-labs.com/cm/cs/pearls/) - Jon Bentley
+* [Programming Pearls](http://www.cs.bell-labs.com/cm/cs/pearls/) - Jon Bentley
 * [Algorithms for Programmers: Ideas and Source Code](http://www.jjj.de/fxt/fxtbook.pdf) (PDF)
 * [Sequential and parallel sorting algorithms](http://www.inf.fh-flensburg.de/lang/algorithmen/sortieren/algoen.htm)
 * [Text Algorithms](http://igm.univ-mlv.fr/~mac/REC/text-algorithms.pdf) (PDF)