https://digital.katalog.queersearch.org/s/katalog/item/44235, “The Writings of Dr. Magnus Hirschfeld: A Bibiography”, https://digital.katalog.queersearch.org/s/katalog/item/49273, QueerSearch, accessed 14. März 2025, https://digital.katalog.queersearch.org/s/katalog/item/27705