↑ Gotlieb, Marc, "The Painter's Secret: Invention and Rivalry from Vasari to Balzac", p. 473, The Art Bulletin, Vol. 84, No. 3 (Sep., 2002), pp. 469–490, JSTOR
↑ E. G. Thomsen and H. H. Thomsen, 'Early Wire Drawing Through Dies', Journal of Manufacturing Science and Engineering, 96.4 (November 1974), 1216–21.