1. E. W. Hobson, “Squaring the Circle,” a His tory of the Problem (Cambridge, 1913; re printed by Chelsea Publishing Company, New York, 1953).
2. J. H. Lambert, “Mémoiresur quelques pro priétés rémarquables des quantités tran scendentes circulates et logarithmiques,” Histoire de l‘Académie de Berlin, 1761 (1768).
3. F. Lindemann, “Ueber die Zahl π,” Malhe malische Annalen, 20 (1882), 213–225.
4. J. Wallis, Arithmetica Infinitorum (1655).
5. R. C. Archibald, Outline of the History of Mathematics (6th ed.; Buffalo, N. Y.: The Mathematical Association of America, 1949), p. 40.