Participation in international congresses and conferences

• International Congress of Mathematicians, Helsinki, 1978, 45-minute invited talk "Global and local aspects of the theory of complex diffe- rential equations" in the section of ordinary differential equations;
• International Congress of Mathematicians, 1990, 45-minute invited talk "Finiteness theorems for limit cycles" in the section of ordinary differential equations;
• Equadiff, Barcelona, 1991, Plenary lecture "Finiteness theorems for limit cycles and Hilbert-Arnold problem;