Encyclopedia
Britannica Intermediate Online. "Michelangelo" <http:/search.ebi.eb.com/ebi/article/0,6101,3565500.html>
February 2000
Kren,
Emil and Marx, Daniel. "Web Gallery of Art"
<http://www.kfki.hu/~arthp/index.html>
February 2000
Museum of Science, Boston. "Exploring Leonardo" 1997 <http://www.mos.org/sln/Leonardo> January 2000.
Periodicals
Kids Discover Magazine. "Leonardo da Vinci" Kids Discover 1998.