1. Continued Fractions;Khinchin,1961
2. Zur metrischen Kettenbruchtheorie;Khintchine;Compositia Math.,1936
3. Introduction to the theory of Diophantine approximations;Cassels,1961
4. Metrische Kettenbruchprobleme;Khintchine;Compositia Math.,1935
5. Continued fraction expansion of 213(N);Von Neumann;Math. Tables and Other Aids Comput.,1955