- ↑ Checklist of CITES Species Part 1 CITES species index, 2011
- ↑ Berger, Alwin, 1929 <![CDATA[Kakteen. Anleitung zur Kultur und Kenntnis der wichtigsten eingeführten Arten, Part of a series, 'Illustrierte Handbücher sukkulenter Pflanzen.' See also Doweld & Greuter (2001:879-885) in Taxon 50:3]]>
- ↑ Doweld, Alexander, and Werner Greuter, 2001Nomenclatural notes on Notocactus and on Alwin Berger's "Kakteen" Taxon, vol. 50, no. 3, Available online at http://www.jstor.org/stable/1223717
- ↑ 4.0 4.1 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