References
Ballard, H.E., Jr. 1992. Systematics of the Viola Section Viola in North America north of Mexico. M.S. thesis, Central Mich. Univ., Mount Pleasant. Google Scholar
Ballard, H.E., Jr. 1992. Systematics of the Viola Section Viola in North America north of Mexico. M.S. thesis, Central Mich. Univ., Mount Pleasant. Google Scholar