- ↑ Torrey, J., 1858-07Report on the United States and Mexican Boundary Survey, made under the direction of the secretary of the interior. Botany of the Boundary.
- ↑ 2.0 2.1 Roskov Y., Kunze T., Orrell T., Abucay L., Paglinawan L., Culham A., Bailly N., Kirk P., Bourgoin T., Baillargeon G., Decock W., De Wever A., Didžiulis V. (ed) (2014). "Species 2000 & ITIS Catalogue of Life: 2014 Annual Checklist". Catalogue of Life. Species 2000: Reading, UK. Ginkuhà 26 Mayo 2014.CS1 maint: multiple names: authors list (link) CS1 maint: extra text: authors list (link)
- ↑ ITIS: The Integrated Taxonomic Information System. Orrell T. (custodian), 26 Abril 2011
