International conference "Theory of approximation of functions and its applications" dedicated to the 70 th birthday of the corresponding member of NASU Professor O. I. Stepanets (1942 - 2007) - Romanyuk, A. S.; Samoilenko, A. M.; Serdyuk, A. S.; Sokolenko, I. V. (Ukrains’kyi Matematychnyi Zhurnal, 2012)