Cassels, J. W. S. An Introduction to Diophantine Approximations. Cambridge, England: Cambridge
University Press, 1957.Davenport, H. and Roth, K. F. "Rational
Approximations to Algebraic Numbers." Mathematika2, 160-167,
1955.Roth, K. F. "Rational Approximations to Algebraic Numbers."
Mathematika2, 1-20, 1955.Roth, K. F. "Corrigendum
to 'Rational Approximations to Algebraic Numbers.' " Mathematika2,
168, 1955.