1. Die Schwangerschaftsdiagnose aus dem Harne,1930
2. Hippocrates, 460 B.C., 42nd Aphorism of his 5th Book.
3. Magnus Albertus, quoted by Aschheim: Op. cit. (ref. 1).
4. De Conceptu et Generatione Hominis;Rueff,1554
5. Practica Canonica, &c;Savonarola,1560