Torrey, J. & Gray. A (1855) Reports of explorations and surveys : to ascertain the most practicable and economical route for a railroad from the Mississippi River to the Pacific Ocean, made under the direction of the Secretary of War 2(4): 165.
Nesom, G.L. (2012) Taxonomy of Apiastrum, Ammoselinum, and Spermolepis (Apiaceae), Phytoneuron 87: 1–49. Available on line . Accessed 2014 May 5. Circumscribes both Ammoselinum giganteum and Ammoselinum occidentale as synonyms of Spermolepis gigantea (Coulter & Rose) G.L. Nesom (2012) comb. nov..