1. G. F. Voronoi, A Generalization of the Continued Fraction Algorithm (Warsaw Univ., Warsaw, 1896); Collected Works (Akad. Nauk USSR, Kiev, 1952), Vol. 1, pp. 197–391 [in Russian].
2. A. D. Bruno and V. I. Parusnikov, Preprint No. 40, IPM RAN (Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, Moscow, 2005).
3. A. D. Bruno and V. I. Parusnikov, Dokl. Math. 74, 628–632 (2006) [Dokl. Akad. Nauk 410, 12–16 (2006)].
4. Z. I. Borevich and I. R. Shafarevich, Number Theory (Academic, New York, 1966; Nauka, Moscow, 1972).
5. A. D. Bruno and V. I. Parusnikov, Preprint No. 58, IPM RAN (Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, Moscow, 2008).