Albert Einstein (2013). “Einstein on Politics: His Private Thoughts and Public Stands on Nationalism, Zionism, War, Peace, and the Bomb”, p.475, Princeton University Press
Epictetus, Marcus Aurelius, Lucius Annaeus Seneca (2016). “Stoic Six Pack: Meditations of Marcus Aurelius, Golden Sayings, Fragments and Discourses of Epictetus, Letters from a Stoic and The Enchiridion”, p.102, Enhanced Media Publishing
Sir Thomas Browne (1852). “The Works of Sir Thomas Browne: Hydriotaphia. Brampton urns. A letter to a friend, upon occasion of the death of his intimate friend. Christian morals, &c. Miscellany tracts. Repertorium. Miscellanies. Domestic correspondence, journals, &c. Miscellaneous correspondence”, p.131
Letter to "Weird Tales" editor Edwin Baird, printed in "Weird Tales" 3, no. 3 (March 1924); Quoted in "Lord of a Visible World: An Autobiography in Letters" edited by S. T. Joshi, (p. 122), 2000.