https://digital.katalog.queersearch.org/s/katalog/item/40731, “John Henry Mackay (Sagitta) : Anarchist der Liebe”, https://digital.katalog.queersearch.org/s/katalog/item/42696, QueerSearch, accessed 16. Juni 2025, https://digital.katalog.queersearch.org/s/katalog/item/35257