1. A. B. Voronetskii and E. A. Kashina, “Sums of squares in algebraic number fields,” in: Topology and Set Theory [in Russian], Izhevsk (1982), pp. 103–110.
2. E. Hecke, Lectures in Algebraic Number Theory [Russian translation], GITTL, Moscow-Leningrad (1940).
3. G. P. Gogishvili, “On finiteness of the number of certain classes of positive primitive quadratic forms,” Trudy TMI im. Razmadze,45, 778–1100 (1974).
4. L. A. Kogan, B. T. Tashpulatov, and S. R. Faiziev, Representation of Numbers by Quadratic Forms [in Russian], Tashkent (1980).
5. A. V. Malyshev, “On representation of integers by positive quadratic forms,” Trudy Mat. Inst. AN SSSR, 65 (1962).