1. N.A. Bykov. On the Solvability of Multidimensional Linear Functional Equations,

In  Vestnik Kharkovskogo Universiteta, 38, Vysha Shkola, 1988. In Russian.

2. N.A. Bykov. The Smooth Classification of  Structurally Stable  Vector Fields on the Circle, Teorija Funkcyj i Funkcionalnyj Analiz, 52, Naukova Dumka, 1988.

In Russian. English Translation,  Journal of Soviet Mathematics, 52(5):3426--3428, 1990.

3. N.A. Bykov. Smoothly Versal Deformations of Structurally Stable  Vector Fields on the  Circle,  Matematicheskije Zametki, 49(5):26--31, 1990. In Russian.            

English translation,  Mathematical Notes of the Academy of Sciences of the USSR,

49(5--6):459--463, 1991.

4. N.A. Bykov. On the Smooth Equivalence of Singular Vector Fields,

Ukrainian Academy of Sciences Reports, (3):5--7, 1991. In Russian.

5. N.A. Bykov. On the Smooth Classification of Vector Fields and their Deformations

on the Circle,  Proceedings of Congress Singularities, International Symposium,

June 3--8, 1991, page 6,  France, 1991.

6.  N.A. Bykov.  Smooth Invariants of  some Singular Vector Fields,

In Teorija Dinamicheskich Sistem  i  Funkcionalnyj  Analiz, Naukova Dumka, 1993.

In Russian.

7. N.A. Bykov,  Functional Equations and Vector Fields , 1996, In  Dynamical Systems  and  Analysis, Naukova Dumka.

8. Genrich  Belitskii, Nikolai Bykov. Spaces of Cohomologies Associated with Linear Functional Equations, Ergodic Theory and Dynamical Systems, Volume 18, Issue 02. April 1998. pp343-356.