1. A. N. Andrianov, V. G. Zhuravlev: Modular forms and Hecke operators. Translations of Mathematical Monographs, 145. American Mathematical Society, Providence, RI, 1995.
2. M. Bhargava: On the Conway-Schneeberger fifteen theorem. Quadratic forms and their applications (Dublin, 1999), 27–37, Contemp. Math., 272, Amer. Math. Soc., Providence, RI, 2000.
3. V. Blomer, V, J. Brüdern, R. Dietmann: Sums of smooth squares. Compos. Math. 145 (2009), 1401–1441.
4. V. Blomer, G. Harcos: Hybrid bounds for twisted L-functions. J. Reine Angew. Math. 621 (2008), 53–79
5. V. Blomer, G. Harcos: Twisted L-functions over number fields and Hilbert’s eleventh problem, Geom. Funct. Anal. 20 (2010), 1–52