Oleksandr Ivanovych Stepanets' (on his 75th birthday) - A. M. Samoilenko; I. O. Lukovskyi; V. L. Makarov; V. P. Motornyi; P. V. Zaderei; A. S. Romaniuk; A. P. Holub; A. S. Serdiuk; V. V. Savchuk; V. S. Romaniuk (Ukrainian Mathematical Journal, 2017)