https://digital.katalog.queersearch.org/s/katalog/item/47415, “Max Hodann (1894-1946) : Sozialist und Sexualreformer”, https://digital.katalog.queersearch.org/s/katalog/item/51150, QueerSearch, accessed 29. April 2025, https://digital.katalog.queersearch.org/s/katalog/item/35208