RomanyukA.S. and SamoilenkoA.M. 2008. Bogolyubov Readings-2008. International Conference "Differential Equations, Theory of Functions and Applications" (on the occasion of the 70th anniversary of academician AM Samoilenko). Ukrains’kyi Matematychnyi Zhurnal. 60, 12 (Dec. 2008), 1722.