^JSTORRaphael's Tapestries and Their Cartoons,John White, John Shearman, The Art Bulletin, Vol. 40, No. 3 (Sep., 1958), pp. 193-221. Rather oddly, both Jones & Penny and Grove Art say, wrongly, that the V&A have eight of the ten cartoons.
^Quoted in Wölffin, Heinrich; Classic Art; An Introduction to the Renaissance, p. 108, 1952 in English (1968 edition), Phaidon, New York.