LITTRELL, J L Time of opening of the vaginal closure membrane in weanling guinea pigs in relation to concentration of estrogen. [electronic resource] - The Anatomical record Mar 1946 - 367 p. digital Publication Type: Journal Article ISSN: 0003-276X Subjects--Topical Terms: AnimalsEstrogensFemaleGenitalia--growth & developmentGuinea PigsHumansOvary--metabolismVagina