@article {532,
	title = {North American Flora. New York Botanical Garden},
	volume = {33},
	year = {1922},
	author = {Rydberg}
}
@article {341,
	title = {Das Pflanzenreich / Engler},
	volume = {4(280)},
	year = {1922},
	author = {Zahn}
}
