1. Römische Mitteilungen, vi. (1891), pp. 208 ff
2. Bonner Studien (Berlin, 1890), pp. 223 ff.
3. Journal of Roman Studies, xiii, p. 164
4. Murray H.J.R. , History of Chess, p. 161.
5. Transactions of the Cumberland and Westmorland Antiquarian Society, 1913, p. 338, and 1926, p. 444