Holland, Jeffrey R. (1973). Mark Twain's Religious Sense: The Viable Years, 1835–1883 (PhD thesis). Yale University. OCLC367235370. ProQuest2152787340.
Holland, Jeffrey R. (1973). Mark Twain's Religious Sense: The Viable Years, 1835–1883 (PhD thesis). Yale University. OCLC367235370. ProQuest2152787340.