By the late 1800s trees along the streets of New York (as distinct from those in parks) were a dwindling urban resource, their shrinking numbers a vivid mark of irrevocable alteration of Manhattan’s topography caused by commercial development… The young, fenced-in tree of Spring Showers was a sign not only of nature and the seasons but also of human intervention to reestablish this natural cycle in the city by planting new trees. Although Stieglitz refers to the street cleaner in his title [in Camera Notes], he took the photograph from a vantage point that made the slender young tree and its delicate branches more central to the elongated composition and more distinct than the human figure. 
Alfred Stieglitz remains today the uncontested doyen of the photographic world. Through the publications he edited, the galleries he ran, and the sheer force of his own images, he fought to establish photography as a means of creative expression. To advance this cause he also promoted the photogravure process as a method of original printmaking. Among the hundreds of gravures presented in Camera Work were Stieglitz’s own often perfect articulations of his “straight" and radical aesthetic stance. The October 1911 issue contained sixteen remarkable photogravures by Stieglitz, including such classics as The Steerage, The Hand of Man, and The Terminal. The selection closed with the delicate Spring Showers, New York. By finding such beauty within the confines of Manhattan, Stieglitz reminded his readers that, to have a chance of succeeding, every creative quest must emanate from the soul. 
Crawford, William. The Keepers of Light. Dobbs Ferry: Morgan and Morgan, 1979. fig. 99
Davis, Keith F. An American Century of Photography: From Dry Plate to Digital. Kansas City, Mo: Hallmark Cards, 1999. Print. P. 63
Doty, Robert M. Photo-secession: Photography As a Fine Art. N.Y: Eastman, 1960. plate IV.
Frizot, Michael. New History of Photography. Place of publication not identified: Pajerski, 1999. Print p. 320
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 270
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Homer, William I, Catherine Johnson, and Alfred Stieglitz. Stieglitz and the Photo-Secession, 1902. London: Penguin Putnam, 2002. Cover
Johnston, Patricia A. Seeing High & Low: Representing Social Conflict in American Visual Culture. Berkeley: University of California Press, 2006. fig 11.7
Kruse, Margret. Kunstphotographie Um 1900: D. Sammlung Ernst Juhl; Hamburg: Museum für Kunst u. Gewerbe, 1989 pl. 864
Madigan, Mary J. S, and Susan Colgan. Prints & Photographs: Understanding, Appreciating, Collecting. , 1983 p. 131
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Peterson, Christian A. Camera Work: Process & Image : [exhibition, Minneapolis, Minneapolis Institute of Arts, August 31-November 3, 1985, Seattle, Seattle Art Museum, November 22, 1985-February 2, 1986]. Minneapolis: Minneapolis Institute of arts, 1985. p. 71.
Pollack, P. The Picture History of Photography: From the Earliest Beginnings to the Present Day. New York: Harry N. Abrams, Inc, 1998. p. 268
Stieglitz, Alfred, Richard Whelan, and Sarah Greenough. Stieglitz on Photography: His Selected Essays and Notes. New York, NY: Aperture Foundation, 2000. p. 115
Stieglitz, Alfred, and Dorothy Norman. Alfred Stieglitz. New York: Aperture, 1976. p. 33.
Trachtenberg, Alan. Reading American Photographs: Images As History : Mathew Brady to Walker Evans. New York: Hill and Wang, 2008. pl. 66
Whelan, Richard. Alfred Stieglitz: A Biography, 1997. pp. 310-311
 Lukitsh, Joanne. "Alone on the Sidewalks of New York: Alfred Stieglitz’s Photography, 1892 – 1913." Seeing High Et Low / Ed. by Patricia Johnston. (2006): 210-227
 Peterson, Christian A. Camera Work: Process & Image : [exhibition, Minneapolis, Minneapolis Institute of Arts, August 31-November 3, 1985, Seattle, Seattle Art Museum, November 22, 1985-February 2, 1986]. Minneapolis: Minneapolis Institute of arts, 1985.