Kazan medical journalKazan medical journal0368-48142587-9359Eco-Vector7789310.17816/kazmj77893MiscellaneousTiming of conception. Vollkmann (Mon. f. Geh. u. G., 73, H ½)150119272311281281208202112082021Copyright © 1927, Board E.1927<p>Based on the accurate determination of the age of embryos, the author concluded that in almost half of all cases conception falls in the first half of the interval between menstruations.</p>Kazan Medical archiveКазанский медицинский архив