https://digital.katalog.queersearch.org/s/katalog/item/43357, https://digital.katalog.queersearch.org/s/katalog/item/42069, and https://digital.katalog.queersearch.org/s/katalog/item/43057, “Sexual Behavior in the Human Male”, https://digital.katalog.queersearch.org/s/katalog/item/49684, QueerSearch, accessed 2. Mai 2025, https://digital.katalog.queersearch.org/s/katalog/item/26087