1. B. A. Venkov, Elementary Number Theory, Wolters-Noordhoff, Groningen (1970).
2. A. M. Istamov, ?Asymptotics of second-order integral matrices lying in a given hyperbolic region and belonging to a given residue class,? J. Sov. Math.,19, No. 2 (1982).
3. Yu. V. Linnik, ?Representation of large numbers by positive, ternary quadratic forms,? Izv. Akad. Nauk SSSR, Ser. Mat.,4, Nos. 4/5, 363?402 (1940).
4. Yu. V. Linnik, ?Some applications of the Lobachevskii geometry to the theory of binary quadratic forms,? Dokl. Akad. Nauk SSSR,93, No. 6, 973?974 (1953).
5. Yu. V. Linnik, ?New arithmetic applications of Lobachevskii geometry,? Dopovidi Akad. Nauk Ukr. RSR, No. 2, 112?114 (1955).