Sources

http://weblog.ceicher.com/archives/2002/08/the_history_of_pigment.html

http://lilinks.com/mara/history.html

http://www.webexhibits.org/pigments/intro/index.html

http://www.webexhibits.org/pigments/intro/early.html

http://www.vanaken.com/history.htm

http://www.paintmaking.com/grinding_egg_tempera.htm

http://www.scribd.com/doc/44140/Egg-Tempera-Painting

http://www.brandywinemuseum.org/news_print/news058_print.html