document: ITIS & Species 2000 Catalogue of Life Management Hierarchy; M. Ruggiero & D. Gordon, eds. 2011. Consensus Management Hierarchy for the ITIS & Species2000 Catalogue of Life. Contributors: Nicolas Bailly, Thierry Bourgoin, Richard Brusca, Thomas Cavalier-Smith, Daphne Fautin, Dennis Gordon, Gerald Guala, Michael Guiry, Paul Kirk, Elliot Lefkowitz, David Mabberly, David Maddison, Alan Paton, Michael Ruggiero, Peter Stevens, and Brian Tyndall
website: <a href="http://www.cbif.gc.ca/itisca/">ITIS*<sup>ca</sup></a>;
website: Angiosperm Phylogeny Website, 2012; Angiosperm Phylogeny Website, botanical information system at the Missouri Botanical Garden, available at http://www.mobot.org/MOBOT/research/APweb/
database: NODC Taxonomic Code;
database: The PLANTS Database; National Plant Data Center, NRCS, USDA. Baton Rouge, LA 70874-4490 USA. http://plants.usda.gov
CD-ROM: Checklist of CITES Species Part 2 History of CITES listings; UNEP-WCMC (Comps.) 2011. Checklist of CITES species (CD-ROM). CITES Secretariat, Geneva, Switzerland, and UNEP-WCMC, Cambridge, United Kingdom. ISBN 2-88323-030-7. Available online at http://www.cites.org/eng/resources/pub/checklist11/index.html or from CITES Secretariat, Chemin des Anémones, 1219 Châtelaine, Genève, Switzerland
database: The PLANTS Database; National Plant Data Center, NRCS, USDA. Baton Rouge, LA 70874-4490 USA. http://plants.usda.gov
Hunt, David 2006-05-01. The New Cactus Lexicon: Text. dh books. Milborne Port, England. x + 373. 0-9538134-5-2. .
Alexander, Edward F. 2001-01-01. The Cactus Family. . . 776. 0-88192-498-9. .