1. Proof of the Littlewood conjecture for infinitely many pairs;Bottorff;Indian J. Pure Appl. Math.,1977
2. On real quadratic number fields and simultaneous diophantine approximation;Burger;Monatshefte Math.,1999
3. On the product of three homogeneous linear forms and indefinite ternary quadratic forms;Cassels;Philos. Trans. Roy. Soc. London Ser. A,1955
4. Verallgemeinerung eines Satzes aus der Lehre von den Kettenbrüchen nebst einigen Anwendungen auf die Theorie der Zahlen;Dirichlet;S. B. Preuss. Akad. Wiss.,1842
5. A convergence problem connected with continued fractions;Larcher;Proc. Amer. Math. Soc.,1988