Theodore Parker (1853). “Two Sermons Preached Before the Twenty-eighth Congregational Society in Boston: On the 14th and 21st of November, 1852, on Leaving Their Old and Entering a New Place of Worship”, p.58
Bertrand Russell (1944). “Pamphlets: The value of free thought; Ideas that have harmed mankind; Ideas that have helped mankind; The faith of a rationalist”