https://digital.katalog.queersearch.org/s/katalog/item/40404, “Magnus Hirschfeld und seine Gäste: Das Exil-Gästebuch 1933-1935”, https://digital.katalog.queersearch.org/s/katalog/item/49575, QueerSearch, accessed 29. April 2025, https://digital.katalog.queersearch.org/s/katalog/item/55300