https://digital.katalog.queersearch.org/s/katalog/item/43573, “Der ruhelose Rebell. Karl Plättner 1893-1945”, https://digital.katalog.queersearch.org/s/katalog/item/47657, QueerSearch, accessed 15. Mai 2025, https://digital.katalog.queersearch.org/s/katalog/item/26454