Max Beckmann, Barbara Copeland Buenger (1997). “Self-Portrait in Words: Collected Writings and Statements, 1903-1950”, p.304, University of Chicago Press
Alexander Pope, Alexander Chalmers (1807). “A Supplementary Volume to the Works of Alexander Pope, Esq: Containing Pieces of Poetry, Not Inserted in Warburton's and Warton's Editions : and a Collection of Letters, Now First Published”, p.311
Frederick K. Goodwin, Kay Redfield Jamison (2007). “Manic-Depressive Illness: Bipolar Disorders and Recurrent Depression”, p.40, Oxford University Press