Joshi, S. T. & Schultz, David E.: An H. P. Lovecraft Encyclopedia, s. 50–55. Westport, Connecticut: London: Greenwood Publishing Group, 2001. ISBN 978-0-313-31578-7. Google-kirjat. (englanniksi)
sf-encyclopedia.com
Edwards, Malcolm & Langford, David: Derleth, August (Toim. John Clute & David Langford) The Encyclopedia of Science Fiction. 24.7.2023. London & Reading: SFE Ltd. & Ansible Editions. Viitattu 14.8.2023. (englanniksi)
Nicholls, Peter; Edwards, Malcolm; Feeley, Gregory & Langford, David: Arkham House (Toim. John Clute & David Langford) The Encyclopedia of Science Fiction. 9.4.2023. London & Reading: SFE Ltd. & Ansible Editions. Viitattu 14.8.2023. (englanniksi)