title: [Valentin Ivanovich Pokrovskiĭ (on his 50th birthday)].
mesh_terms: D004813:Epidemiology / Q000266:history; D049673:History, 20th Century; D014586:USSR
vernacular_title: Valentin Ivanovich Pokrovskiĭ (k 50-letiiu so dnia rozhdeniia).