USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner's Sons, New York. Vol. 2: 67.
(source URL: http://commons.wikimedia.org/wiki/File:Silene_gallica_drawing.jpg)
