5) Sources

http://www.geoman.com/Vitruvius.html
http://www-history.mcs.st-and.ac.uk/history/Mathematicians/Leonardo.html

Leonardo de uitvinder Domus software
Leonardo da Vinci - Mathematics and the Liberal Arts

1) Biography

2) The controversial Replica of Leonardo da Vinci's Adding Machine

3) The Vitruvian Man

4) Quotations by Leonardo da Vinci

6) If you want to know more...