For Thermopsis
Chen, C.J., M.G. Mendenhall, and B.L. Turner. 1994. Taxonomy of Thermopsis (Fabaceae) in North America. Ann. Missouri Bot. Gard. 81: 714-742.
Chen, Mendenhall, & Turner in FNA (in prep.)
Isely, D. 1981. Leguminosae of the United States. III. Subfamily Papilionoidae: Tribes Sophoreae, Podalyriaeae, Loteae. Memoirs N.Y. Bot. Gard. 25: 1-264.
Isely, D. 1998. Native and naturalized Leguminosae (Fabaceae) of the United States (exclusive of Alaska and Hawaii). Monte L. Bean Life Science Museum, Brigham Young Univ., Provo, UT.
Larisey. M.M. 1940b. A revision of the North American species of the genus Thermopsis. Ann. Mo. Bot. Garden 27: 245-258.