Hirst, Text-Book of Obstetrics, 1899, p. 67.
The earliest story of the kind with which I am acquainted, that of a widow who was thus impregnated by a married friend, is quoted in Schurig's Spermatologia (p. 224) from Amatus Lusitanus, Curationum Centuriæ Septum, 1629.
Janke, Die Willkürliche Hervorbringen des Geschlechts, p. 238.