@book {156,
	title = {An Illustrated Flora of the Northern United States, Canada And The British Possessions},
	volume = {3},
	year = {1913},
	publisher = {Charles Scribner{\textquoteright}s Sons},
	organization = {Charles Scribner{\textquoteright}s Sons},
	edition = {2},
	author = {Nathaniel Lord Britton and Addison Brown}
}
@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}
}
