[The incidence of twin births].
D000367:Age Factors; D000858:Anovulation; D001723:Birth Rate; D002170:Canada; D003075:Coitus; D005060:Europe; D005260:Female; D005860:Germany, West; D006801:Humans; D007564:Japan; D008297:Male; D011044:Poland; D011247:Pregnancy; D011272:Pregnancy, Multiple; D013223:Statistics as Topic; D014427:Twins; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic; D014481:United States
Uber die Häufigkeit von Zwillingsgeburten