W.T. Walters, letter to J.F. Cropsey, Baltimore, Maryland, April 20, 1860. J.F. Cropsey, letter to S.P. Avery, London, England, June 5, 1860. W.T. Walters, letter to J.F. Cropsey, Baltimore, Maryland, June 26, 1860. "Art Items," New York Daily Tribune, June 27, 1860, p. 7. J.F. Cropsey, letter to W.T. Walters, July 27, 1860. "Sketchings: Domestic Art Group," The Crayon, July 7, 1860. "The Seasons," Milwaukee Daily Sentinel, July 26, 1860, p. 2. "Art Gossip," The Cosmopolitan Art Journal, September 4, 1860. W.S. Talbot, Jasper F. Cropsey 1823-1900, Ph.D. dissertation, New York University, 1972, pp. ix, 149-52, 408-09, fig. 113, illustrated (as Winter: Switzerland). M.Y. Hutson, George Henry Durrie (1820-1863) American Winter Landscapist: Renowned through Currier and Ives, exhibition catalogue, Santa Barbara, California, 1977, p. 82 (as Simplon Pass, Switzerland). W.R. Johnston, William and Henry Walters, The Reticent Collectors, Baltimore, Maryland, 1999, pp. 16-17. A.J. Carvel, "Winter, 1860," Important American Paintings, exhibition catalogue, New York, 2006, n.p., pl. 20, illustrated (as Winter). A.J. Carvel, "Important American Paintings," Antiques and The Arts Weekly, October 13, 2006, p. 30, illustrated (as Winter).