@book {235, title = {An illustrated flora of the northern United States, Canada and the British possessions : from Newfoundland to the parallel of the southern boundary of Virginia, and from the Atlantic Ocean westward to the 102d meridian (1913)}, year = {1913}, publisher = {New York : C. Scribner{\textquoteright}s sons}, organization = {New York : C. Scribner{\textquoteright}s sons}, url = {http://www.archive.org/details/illustratedflora03brit}, author = {Nathaniel Lord Britton and Addison Brown} }