https://digital.katalog.queersearch.org/s/katalog/item/40846, “Mordsache Röhm: Hitlers Durchbruch zur Allein-Herrschaft 1933-1934”, https://digital.katalog.queersearch.org/s/katalog/item/47507, QueerSearch, accessed 29. April 2025, https://digital.katalog.queersearch.org/s/katalog/item/17101