References for Campanulaceae
Bowden, W.M. 1959. Cytotaxonomy of Lobelia L. sect. Lobelia, 1. Three diverse species and seven small-flowered species. Can. J. Genet. Cytol. 1:49-64.
McVaugh, R. 1941. A monograph on the genus Downingia. Mem. Torr. Bot. Club 194:1-57.
Morin, N. 1983. Systematics of Githopsis (Campanulaceae). Syst. Bot. 8:436-468.
Shetler, S.G. 1963. A checklist and key to the species of Campanula native or commonly naturalized in North America. Rhodora 65:319-337.

Source for the Reference Lists

George W. Douglas, Del Meidinger and Jim Pojar. 1998-2002. Illustrated Flora of British Columbia.