[2] A. A. Mullin: Properties of mutants. Bull. Amer. Math. Soc. 67 (1961), p. 82.
[4] A. Y. Khinchin:
Three pearls of number theory. Garylock Press, Rochester, New York, (1962).
MR 0046372
[5] B. L. Van der Waerden: Beweis einer Baudetschen Vermutang. Nieuw. Arch. Wiskunde, 15 (1927) p. 212-216.