https://digital.katalog.queersearch.org/s/katalog/item/40860, “Der Freiheitssucher: Psychologie einer Entwickelung”, https://digital.katalog.queersearch.org/s/katalog/item/39321, QueerSearch, accessed 29. April 2025, https://digital.katalog.queersearch.org/s/katalog/item/26216