Sources:
Leonardo da Vinci (1967) by Kenneth Clark, Penguin Books, London.
Mona Lisa: A Life Discovered (2014) by Dianne Hales, Simon and Schuster, New York.
Leonardo da Vinci (2014) by Peter Bryant, Delphi Classics, East Sussex, UK.
Leonardo (2005) by Frank Zöllner, Taschen, Los Angeles.
Leonardo da Vinci (2017) by Walter Isaacson, Simon and Schuster, New York.
The Lost Mona Lisa (2011) by R. A. Scotti, Bantam Books, UK.
The World of Leonardo (1971) by Robert Wallace, Time-Life, Fairfax, Virginia.
The Renaissance: Studies in Art and Poetry (1873) by Walter Pater, Oxford World’s Classics, Oxford (1998 edition).
Audio:
Concerto No. 2 in G minor, Op. 8, RV 315, "Summer” — Movement 1: Allegro non molto from The Four Seasons by Antonio Vivaldi performed by John Harrison — Violin / Robert Turizziani — Conductor / Wichita State University Chamber Players
"Toccata" from L'Orfeo by Claudio Monteverdi.
Pictures Requiring Attribution:
Dennis Jarvis: https://commons.wikimedia.org/wiki/File:France-003324-Mona-Lisa-(16236519171)
Karl Woermann: https://commons.wikimedia.org/wiki/File:Galeriewerk_Woermann_Mappe_01_25.jpg