http://www-history.mcs.st-andrews.ac.uk/Mathematicians/Riemann.html
http://en.wikipedia.org/wiki/Bernhard_Riemann
http://www.mathematicianspictures.com/Mathematicians/Riemann.htm
http://www.emis.de/classics/Riemann/
_ Georg Friedrich Bernard Riemann
http://jp.youtube.com/watch?v=xuRf88IsobQ
_ Right Riemann Sum
http://jp.youtube.com/watch?v=ICpE5VLAHF0
_ Riemann sum of ln(x-2) using average of left and right
http://jp.youtube.com/watch?v=44se4U0ynT8