1. Nicholl C. Leonardo Da Vinci: Flights of the Mind. New York: Penguin Books, 2004.
2. MacCurdy E (ed): daVinci L: Notebooks. Definitive Edition in one volume. Old Saybrook, CT: Konecky & Konecky, 2003.
3. Bramly S. Leonardo: The Artist and the Man. New York: Penguin Books, 1988.
4. Freud S. Leonardo da Vinci and a Memory of His Childhood. New York: Barnes & Noble Books, 2003.
5. Nuland SB. Leonardo da Vinci. New York: Penguin Books, 2000.