https://digital.katalog.queersearch.org/s/katalog/item/41921, “Schwester Bruder: Gertrude und Leo Stein”, https://digital.katalog.queersearch.org/s/katalog/item/47690, QueerSearch, accessed 30. April 2025, https://digital.katalog.queersearch.org/s/katalog/item/19402