@book {250,
	title = {Species Plantarum},
	volume = {2},
	year = {1753},
	author = {Linnaeus}
}
@book {524,
	title = {Histoire Naturelle des vegetaux},
	volume = {10},
	year = {1841},
	publisher = {Librairie Encyclopedique de Roret},
	organization = {Librairie Encyclopedique de Roret},
	address = {Paris},
	author = {Edouard Spach}
}
@book {218,
	title = {Flora of North America},
	series = {Magnoliophyta: Asteridae(in part): Asteraceae, part1},
	volume = {19},
	year = {2006},
	pages = {202-203},
	publisher = {Oxford University Press, Inc.},
	organization = {Oxford University Press, Inc.},
	address = {New York},
	url = {www.fna.org},
	author = {Strother, John L},
	editor = {Flora of north America Editorial Commitee ,}
}
