https://digital.katalog.queersearch.org/s/katalog/item/40426, “Three Early Works: Nassau-Taxis Postal Contract - German Postal Pincipality - Greater Germany Program”, https://digital.katalog.queersearch.org/s/katalog/item/49217, QueerSearch, accessed 29. April 2025, https://digital.katalog.queersearch.org/s/katalog/item/26473