GlushchenkoA. A.; LyashkoI. I.; MitropolskiyY. A.; ParasyukI. O.; SamoilenkoA. M.; SamoilenkoV. G. V. G. Georgii Mykolaiovych Polozhyi (on his 90th birthday). Ukrains’kyi Matematychnyi Zhurnal, v. 56, n. 4, p. 560-561, 25 Apr. 2004.