[6] Suetonius: “Soleis mularum argenteis.”
[7] Pliny: “Jumentis suis soleas ex auro induere.”
[8] Fosbroke, Dictionary of Antiquities.
[9] Knight’s Mechanical Dictionary.
[10] Alexander Adam, LL. D., Roman Antiquities.
[11] Archæologia, vol. xlvii.
[12] Scribner’s Magazine, November, 1894.
[13] John Beckman, A History of Inventions.
[14] Fosbroke, Archæologia, vol. iii.
[15] Notes and Queries, series 3, vol. v. 1864.