https://digital.katalog.queersearch.org/s/katalog/item/40561, “Briefe und Antworten: Band 2: 1951-1969”, https://digital.katalog.queersearch.org/s/katalog/item/45941, QueerSearch, accessed 28. April 2025, https://digital.katalog.queersearch.org/s/katalog/item/16705