1. J. W. S. Cassels, An Introduction to Diophantine Approximations, Cambridge University Press, 1957.
2. D. Gale, The Theory of Linear Economic Models, McGraw-Hill, New York, 1960.
3. On a linear Diophantine equation
4. L. E. Dickson, History of the Theory of Numbers, Vol. 1, Chelsea, New York 1952, p. 124.
5. E. Artin, Theory of Algebraic Numbers, Lecture Notes, Gottingen, 1956.