Nyberg, Svein Olav, "The union of egoists"(PDF), Non Serviam, Oslo, Norway: Svein Olav Nyberg, 1: 13–14, OCLC47758413, diarsipkan dari versi asli(PDF) tanggal 12 October 2012, diakses tanggal 1 September 2012
Nyberg, Svein Olav, "The union of egoists"(PDF), Non Serviam, Oslo, Norway: Svein Olav Nyberg, 1: 13–14, OCLC47758413, diarsipkan dari versi asli(PDF) tanggal 12 October 2012, diakses tanggal 1 September 2012
Karl Heinrich Ulrichs had begun a journal called Prometheus in 1870, but only one issue was published. Kennedy, Hubert, Karl Heinrich Ulrichs: First Theorist of Homosexuality, In: 'Science and Homosexualities', ed. Vernon Rosario (pp. 26–45). New York: Routledge, 1997.
Nyberg, Svein Olav, "The union of egoists"(PDF), Non Serviam, Oslo, Norway: Svein Olav Nyberg, 1: 13–14, OCLC47758413, diarsipkan dari versi asli(PDF) tanggal 12 October 2012, diakses tanggal 1 September 2012
