1. A. P. Ogg, “On a convolution of L-series,” Invent. Math., 7, 297–312 (1969).
2. J. Hoffstein and D. Ramakrishnan, “Siegel zeros and cusp forms,” Int. Math. Res. Notices, No. 6, 279–308 (1995).
3. E. P. Golubeva and O. M. Fomenko, “Values of the Dirichlet series associated with modular forms at the points s = 1/2, 1,” Zap. Nauchn. Semin. LOMI, 134, 117–137 (1984).
4. M. B. Barban, “The “large sieve” method and its applications in number theory,” Usp. Mat. Nauk., 21, 51–102 (1966).
5. M. Eichler, “Quadratische Formen und Modulfunktionen,” Acta Arithm., 4, 217–239 (1958).