1. S. Lang, Algebra.Addison-Wesley, New York, 1965.
2. I. Shafarevich, Foundations of Algebraic Geometry. (Russian) “Nauka,”Moscow, 1972.
3. M. Krein and M. Neimark, Method of quadratic forms for separation of roots of polynomials. (Russian) “GNTI,”Kharkov, 1936.
4. G. Khimshiashvili, On the number of zeroes of a real polynomial endomorphism.Bull. Acad. Sci. Georgia,146(1992), No.3, 469–473.
5. T. Aliashvili, On the topological degree of a polynomial endomorphism. (Russian)Collection of works in homology theory. 6. (Russian) Trudy Tbiliss. Mat. Inst. Razmadze 103, to appear.