For Inula
Arriagada, J.E. 1998. The genera of Inuleae (Compositae; Asteraceae) in the southeastern United States. Harvard Papers in Botany 3: 1-48. Google Scholar
Brunton, D.F., M.J. Oldham, and A.V. Gilman. 2022. Himalayan Elecampane, Inula racemosa (Asteraceae), in North America. Rhodora 123(919) 19-30: Google Scholar
Cronquist, A. 1980. Asteraceae, Volume I, Vascular flora of the Southeastern United States. University of North Carolina Press, Chapel Hill, N.C. Google Scholar
Harriman, N.A. 2006a. Inula. In Flora of North America Editorial Committee. 2006a. Flora of North America north of Mexico. Volume 19, Magnoliophyta: Asteridae, part 6: Asteraceae, part 1. Oxford Univ. Press, New York, NY. 579 pp. Google Scholar