Althoen, S.C.; King, L.; Schilling, K. (Março de 1993). «How Long Is a Game of Snakes and Ladders?». The Mathematical Association. The Mathematical Gazette. 77 (478): 71–76. JSTOR3619261. doi:10.2307/3619261
Hugh-Jones, E.M. (Junho de 1952). «The American Economy, 1860–1940. by A. J. Youngson Brown». Wiley. The Economic Journal. 62 (246): 411–414. JSTOR2227038. doi:10.2307/2227038
Althoen, S.C.; King, L.; Schilling, K. (Março de 1993). «How Long Is a Game of Snakes and Ladders?». The Mathematical Association. The Mathematical Gazette. 77 (478): 71–76. JSTOR3619261. doi:10.2307/3619261
Hugh-Jones, E.M. (Junho de 1952). «The American Economy, 1860–1940. by A. J. Youngson Brown». Wiley. The Economic Journal. 62 (246): 411–414. JSTOR2227038. doi:10.2307/2227038