- ↑ database, NODC Taxonomic Code, 1996
- ↑ Checklist of CITES Species Part 1 CITES species index, 2011
- ↑ database, The PLANTS Database, 2000
- ↑ database, The PLANTS Database, 1996
- ↑ U. S. Fish and Wildlife Service, (1993) Endangered and Threatened Wildlife and Plants; Reclassification of the Pland Pediocactus sileri (Siler Pincushion Cactus) From Endangered to Threatened Status Federal Register, vol. 58, no. 246
- ↑ 6.0 6.1 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)
- ↑ (Canada);http://siit.conabio.gob.mx (Mexico) ITIS Global: The Integrated Taxonomic Information System
