https://digital.katalog.queersearch.org/s/katalog/item/43960, “Alfred Blaschko (1858-1922) and the Problem of Sexually Transmitted Diseases in Imperial and Weimar Germany: A Bibliography”, https://digital.katalog.queersearch.org/s/katalog/item/50115, QueerSearch, accessed 1. Mai 2025, https://digital.katalog.queersearch.org/s/katalog/item/27165