1. Delieuvin, V. & Frank, L. Léonard de Vinci (Louvre Editions & Hazan, Paris, 2019).
2. Menu, M. Leonardo da Vinci’s Technical Practice—Paintings, Drawings and Influence (Hermann, 2017).
3. de Viguerie, L., Walter, P., Laval, E., Mottin, B. & Sole, V. Revealing the sfumato technique of Leonardo da Vinci by X-ray fluorescence spectroscopy. Angew. Chem. 49(35), 6125–6128 (2010).
4. Ravaud, E., Eveno, M. & Bastian, G. L’art de la matière, l’art et la manière. In Léonard de Vinci (ed. Delieuvin, V.) 358–369 (Louvre Editions & Hazan, Paris, 2019).
5. Keith, L., Roy, A., Morrison, R. & Schade, P. Leonardo da Vinci’s virgin of the rocks: Treatment, technique and display. Natl. Gallery Techn. Bull. 32, 32–56 (2011).