@article {8251,
	title = {Helianthus laetiflorus and Helianthus rigidus _ hybrids or species},
	journal = {Rhodora},
	volume = {65},
	year = {1963},
	month = {1963///},
	pages = {121 - 133},
	author = {S. Clevenger and C.B. Heiser}
}
