Popham, R. A. (1941). A key to the genera of the Compositales of northeasten North America (based on vegetables and floral characters). The Ohio state university.
Chicago Style (17th ed.) CitationPopham, Richard Allen. A Key to the Genera of the Compositales of Northeasten North America (based on Vegetables and Floral Characters). Columbus: The Ohio state university, 1941.
MLA (9th ed.) CitationPopham, Richard Allen. A Key to the Genera of the Compositales of Northeasten North America (based on Vegetables and Floral Characters). The Ohio state university, 1941.
Warning: These citations may not always be 100% accurate.