https://digital.katalog.queersearch.org/s/katalog/item/38658, https://digital.katalog.queersearch.org/s/katalog/item/42357, and https://digital.katalog.queersearch.org/s/katalog/item/40404, “Magnus Hirschfelds Exil-Gästebuch - Nachträge und Korrekturen”, QueerSearch, accessed 30. April 2025, https://digital.katalog.queersearch.org/s/katalog/item/56820