(en) John Murray, Handbook for Travellers in Central Italy : Including the Papal States, Rome, and the Cities of Etruria, with a Traveling Map, J. Murray and son, , 568 pages (lire en ligne), p. 39.
Georg Germann, Vitruve et le vitruvianisme : introduction à l'histoire de la théorie architecturale, PPUR presses polytechniques, , 264 pages (lire en ligne), p. 136.