title: [Changes in the incidence of twin births in Czechoslovakia].
mesh_terms: D000328:Adult; D003604:Czechoslovakia; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D011272:Pregnancy, Multiple; D014427:Twins
vernacular_title: Zmény frekvence porodů dvojcat v CSR.