"The 100 best nonfiction books: No 68 - Narrative of the Life of Frederick Douglass, an American Slave by Frederick Douglass (1845)" by Robert McCrum, www.theguardian.com. May 22, 2017.
Sri Aurobindo International Centre of Education (Pondicherry, India), Aurobindo Ghose (1988). “Bulletin Du Centre International D'éducation Sri Aurobindo”
"Refutation of all heresies, Book IX (Fragment 52)". Book by Hippolytus of Rome (3rd century AD), as later translated in Carl Avren Levenson and Jonathan Westphal "Reality" (p. 10), 1994.