Lewis, James R., Oliver, Evelyn Dorothy, Sisung Kelle S. (Editor) (1996), Angels A to Z, Entry: Incubi and Succubi, pp. 218, 219, Visible Ink Press, ISBN0-7876-0652-9
Ha, Douglas. "Succubus". Online Etymology Dictionary. late 14c., alteration (after incubus, giving a masc. form to a word generally felt as of female meaning) of Late Latin succuba
Kramer, Heinrich and Sprenger, James (1486), Summers, Montague (translator – 1928), The Malleus Maleficarum, Part2, chapter VIII, "Certain Remedies prescribed against those Dark and Horrid Harms with which Devils may Afflict Men," at sacred-texts.com