1. Codex Atlanticus, 115a. Richter J-P. The notebooks of Leonardo da Vinci. Compiled and edited from the original manuscripts. New York: Dover Publications; 1883 (reprinted 1970). Vol I, p.15
2. Lives of the painters, sculptors and architects;Vasari,1987
3. Leonardo da Vinci;Marani,2000
4. Vasari, op cit. p.258
5. Leonardo da Vinci on the human body;O'Malley,2003