https://digital.katalog.queersearch.org/s/katalog/item/42102, “Denkbewegungen: Tagebücher 1930-1932, 1936-1937”, https://digital.katalog.queersearch.org/s/katalog/item/48418, QueerSearch, accessed 29. April 2025, https://digital.katalog.queersearch.org/s/katalog/item/19864