http://www-history.mcs.st-andrews.ac.uk/Mathematicians/Riemann.html
http://en.wikipedia.org/wiki/Bernhard_Riemann
http://www.answers.com/topic/bernhard-riemann
http://www.mathematicianspictures.com/Mathematicians/Riemann.htm
http://www.emis.de/classics/Riemann/