The author's citation of dates and documents relies almost exclusively on those in Beltrami's "Documenti e memorie riguardanti la vita e le opere di Leonardo da Vinci" (Milan: Fratelli Treves, 1919). See also Marani's larger publication from 2000 "Leonardo da Vinci: The Complete Paintings" (cited in this database). The catalogue was also reprinted in 2003 (New York: H.N. Abrams).