1. A thorough analysis of the complete history of progesterone purification is still a desideratum. Above all this might be due to source-related problems (e.g. laboratory records etc.). Aside from the mentioned scientific groups the problem of progesterone isolation was also dealt with by the following chemists: Butenandt, Hohlweg and Westphal of Germany (TU Danzig/Schering Berlin) as well as Hartmann and Wettstein of Switzerland (Ciba, Basel). The first papers on the purification of progesterone issued almost simultaneously were the following: Wintersteiner O, Allen WM: Crystalline progestin. J Biol Chem 1934;107:321–336; Hartmann M, Wettstein A: Ein krystallisiertes Hormon aus dem Corpus luteum. Helv Chim Acta 1934;17:878–882; Slotta KH, Ruschig H, Fels E: Reindarstellung der Hormone aus dem Corpus luteum. (Vorl. Mitteil.). Krystallographische Untersuchungen von A Neuhaus. Ber Dtsch Chem Ges 1934;67:1270–1273; Butenandt A, Westphal U, Hohlweg W: Über das Hormon des Corpus luteum. Hoppe-Seyleŕs Zschr Physiol Chem 1934;227:84–98.
2. Slotta KH. Progesterone. Endokrinologie-Informationen 1984;4:164–170. Additionally, copies of laboratory records of WM Allen which are in possession of HH Simmer, Birkenhain 1, D-91054 Bräuningshof.
3. Die Reindarstellung der Hormone aus dem Corpus luteum;Slotta;Klin Wschr,1934
4. Another disciple of Born, Vilhelm Magnus (1871–1929) of Norway, performed similar experiments at the turn of the century. But he published just once on the subject, in 1901. The paper was written in Norwegian language and not noticed by international scientists. See: Simmer HH. The First Experiments to Demonstrate an Endocrine Function of the Corpus Luteum. Part II. Ludwig Fraenkel Versus Vilhelm Magnus. Sudhoffs Archiv 1972;56:76–99.
5. Simmer HH. Zur Geschichte der Endokrinologie der Fortpflanzung. In: Gynäkologie und Geburtshilfe. Grundlagen, Pathologie, Prophylaxe, Diagnostik, Therapie in 3 Bänden. Hrsg: Zander J., Bd. I/1: Sexuelle Differenzierung, Genetik, Fortpflanzung, Kindheit und Pubertät. 2. neu bearb. Aufl. 1987, Georg Thieme Verlag, Stuttgart/New York, 4.3–4.12. This review contains a large register of primary and secondary sources concerning the early history of gynecological endocrinology.