Higginson, Thomas W.. “Views on Socialism”. p. 9. 2018年12月12日閲覧。 “I grew up in the Brook Farm and Fourierite period and have always been interested in all tendencies in that direction.”
Higginson, Thomas Wentworth (1870-06-02). The Sympathy of Religions. First printed in The Radical, Boston, 1871. Retrieved from Gutenberg.org, 2018-05-05.
Nichols, Richard E. (2000年8月20日). “THE MAGNIFICENT ACTIVIST The Writings of Thomas Wentworth Higginson”. 2018年11月5日閲覧。 “His radicalism never dimmed; in 1906, at the age of 83, he joined with Jack London and Upton Sinclair to form the Intercollegiate Socialist Society.”