REFERENCES
- T. M. Apostol, Mathematical Analysis, 2nd edition, Addison-Wesley Publishing Co., Reading, MA, 1974, p. 7.
- G. H. Hardy and F. M. Wright, An Introduction to the Theory of Numbers, 4th edition, Oxford University Press, Fair Lawn, NJ, 1971, p. 46.
- N. J. Lord, The irrationality of e and others, The Math. Gaz. 69 (1985), 213–5.
- I. Niven, Irrational Numbers, Carus Mathematical Monographs 11, MAA, 1967, pp. 7–11.
- G. Pólya and G. Szegő, Problems and Theorems in Analysis, Vol. 2, Springer-Verlag, New York, 1976, p. 154 (problems 258, 259), pp. 361–2.