1. V.C. Dumir, R.J. Hans-Gill and J.B. Wilker, Further contributions to a general theory of view obstruction problems II, J. Number Theory
59, 352–373, 1996.
2. V.C. Dumir, R.J. Hans-Gill and J.B. Wilker, View Obstruction and a conjecture of Schoenberg, Indian J. Pure and Appl. Math.
27, 323–342, 1996.
3. V.C. Dumir, R.J. Hans-Gill and J.B. Wilker, The I
p
Family of View Obstruction problems, Nieuw Archief voor Wiskunde 11, 225–239, 1993.
4. G.H. Hardy and E.M. Wright, An introduction to Number Theory, Fifth Edition, Oxford, 1979.
5. D. König and A. Szücs, Mouvement d’un point abandonné à l’intérieúr d’un cube, Rendiconti del Circ. Mat. di Palermo
36, 79–90, 1913.