Greenberg, 2003. Elsevier Health Sciences Document reference Greendberg, M.I., 2003. Occupational, industrial, and environmental toxicology. Elsevier Health SciencesWeb http://books.google.com/books?id=NnZ23IqU4SoCCitation key Greenberg, 2003Datasheets Prickly pear (Opuntia ficus-indica)
