Diary entry. "Diary and Letters of Rutherford Birchard Hayes: Nineteenth President of the United States". Book edited by Charles Richard Williams, The Ohio State Archaeological and Historical Society, December 12, 1890.
Robert Burton (1824). “The Anatomy of Melancholy,: In which the Kinds, Causes, Consequences, and Cures of this English Malady, ... are -- "traced from Within Its Inmost Centre to Its Outmost Skin."”, p.178