Mark Grigorievich Krein (to the centenary of his birth) - Adamyan, V. M.; Arov, D. Z.; Berezansky, Yu. M.; Gorbachuk, V. I.; Gorbachuk, M. L.; Mikhailets, V. A.; Samoilenko, A. M. (Ukrains’kyi Matematychnyi Zhurnal, 2007)