lecture04: Writing Software for the Mathematical Sciences
http://rosettacode.org/wiki/Rosetta_Code
http://blog.moertel.com/posts/2006-03-01-finding-duplicate-words-in-writing-a-handy-perl-script.html
http://xkcd.com/1171/
http://software-carpentry.org/
http://www.maths.adelaide.edu.au/matthew.roughan/class_notes.html