Clark, T. and K.C. Lund. "Presence of the Indole Alkaloid Reserpine in Bignonia Capreolata L." International Journal of Pharmacognosy and Phytochemical Research. September–November 2012. [1]Archived 2016-03-04 at the Wayback Machine
jstor.org
Alwyn H. Gentry, Bignonia crucigera: A Case of Mistaken Identity, Taxon 24(1): 121-123 (Feb. 1975), a relevant portion of which may be previewed here.
Clark, T. and K.C. Lund. "Presence of the Indole Alkaloid Reserpine in Bignonia Capreolata L." International Journal of Pharmacognosy and Phytochemical Research. September–November 2012. [1]Archived 2016-03-04 at the Wayback Machine