https://digital.katalog.queersearch.org/s/katalog/item/40487 and https://digital.katalog.queersearch.org/s/katalog/item/40488, “Der junge Kurt”, https://digital.katalog.queersearch.org/s/katalog/item/42696, QueerSearch, accessed 29. April 2025, https://digital.katalog.queersearch.org/s/katalog/item/16773