To judge from his snapshot pictures, Stieglitz was watching for moments when the casual life of the street harmonized, when random elements came to buildings. In other words, pictures existed in nature, but only an artist, sensitive to natural harmonies, could identify them. A “Winter Day,” a Fifth Avenue stagecoach ploughing through chaotic masses of snow, is perhaps less pictorial from a painter’s point of view, but for that very reason more original and individual than the others, because it reminds one of nothing else, while most of the others suggest in some way or another faint reminiscences of some school of art. It is a realistic expression of an everyday occurrence of metropolitan life under special atmospheric conditions, rendered faithfully and yet with consummate art. I, as a literary man, would feel proud if I could express a “Winter Day” in words with the same vigor, correctness, and individual note as Mr. Stieglitz in his photographic plate. His achievements in this picture are not merely finger posts for amateur photographers, but for our American art world in general. 
Beaton, Cecil, and Gail Buckland. The Magic Image: The Genius of Photography. London: Pavilion, 1989. p. 100
Greenough, Sarah, and Alfred Stieglitz. Alfred Stieglitz: The Key Set : the Alfred Stieglitz Collection of Photographs. Washington, D.C: National Gallery of Art, 2002. Pl 85
Homer, William I, Catherine Johnson, and Alfred Stieglitz. Stieglitz and the Photo-Secession, 1902. London: Penguin Putnam, 2002.
Homer, William I. Alfred Stieglitz and the Photo-Secession. Boston: Little, Brown and Company, 1983. no. 11.
Johnston, Patricia A. Seeing High & Low: Representing Social Conflict in American Visual Culture. Berkeley: University of California Press, 2006. fig 11.4
Kruse, Margret. Kunstphotographie Um 1900: D. Sammlung Ernst Juhl; Hamburg: Museum für Kunst u. Gewerbe, 1989 pl. 864
Michaels, Barbara L. Gertrude Käsebier: The Photographer and Her Photographs. New York: Abrams, 1992 pl. 26
Stieglitz, Alfred, Richard Whelan, and Sarah Greenough. Stieglitz on Photography: His Selected Essays and Notes. New York, NY: Aperture Foundation, 2000. p. 22
Trachtenberg, Alan. Reading American Photographs: Images As History : Mathew Brady to Walker Evans. New York: Hill and Wang, 2008. pl. 65
 Excerpt: “An Art Critic’s Estimate of Alfred Stieglitz”: Sadakichi Hartmann: In: The Photographic Times: June, 1898: pp. 259-262