Douglas, R. L. (1944). Leonardo da Vinci: His life and his pictures. The University of Chicago Press.
Lua i Stíl Chicago (17ú heag.)Douglas, R. Langton. Leonardo Da Vinci: His Life and His Pictures. Chicago: The University of Chicago Press, 1944.
Lua MLA (9ú heag.)Douglas, R. Langton. Leonardo Da Vinci: His Life and His Pictures. The University of Chicago Press, 1944.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.