For Tragopogon
Cronquist, A. 1980. Asteraceae, Volume I, Vascular flora of the Southeastern United States. University of North Carolina Press, Chapel Hill, N.C. Google Scholar
Soltis, D.E., E.V. Mavrodiev, M.A. Gitzendanner, Y.E. Alexeev, G.T. Godden, and P.S. Soltis. 2022. Tragopogon dubius: multiple introductions to North America and the formation of the New World tetraploids. Taxon 71(6): 1287-1298. Google Scholar
Soltis, D.E., E.V. Mavrodiev, V. Brukhin, E.H. Roalson, D.C. Albach, G.T. Godden, Y.E. Alexeev, M.A. Gitzendanner, C.C. Freeman, V.N. Suárez-Santiago, and P.S. Soltis. 2023. Tragopogon pratensis: multiple introductions to North America, circumscription, and the formation of the allotetraploid T. miscellus. Taxon. Google Scholar
Soltis, P.S. 2006. Tragopogon. 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
Voss, E.G. 1996. Michigan flora: a guide to the identification and occurrence of the native and naturalized seed-plants of the state. Part III, dicots (Pyrolaceae-Compositae). Cranbrook Institute of Science Bulletin No. 61 and Univ. of Mich. Herbarium, Ann Arbor, MI. 622 pp. Google Scholar