http://ekhartman.berkeley.edu/work/ANOVA.pdf

http://www.statsoft.com/textbook/anova-manova/

http://animsci.agrenv.mcgill.ca/servers/anbreed/statisticsII/type1.htm

http://en.wikipedia.org/wiki/Degrees_of_freedom_(statistics)

http://www.pindling.org/Math/Statistics/Textbook/Chapter10_ANOVA/ANOVA.htm

http://statwww.epfl.ch/davison/SM/SMsample.pdf