https://digital.katalog.queersearch.org/s/katalog/item/40926 and https://digital.katalog.queersearch.org/s/katalog/item/40927, “Anrüchig: Bedürfnis-Anstalten in der Großstadt”, https://digital.katalog.queersearch.org/s/katalog/item/48705, QueerSearch, accessed 14. Mai 2025, https://digital.katalog.queersearch.org/s/katalog/item/17220