1. Aldrich, J., Cherney, B. W., Merlin, E., Christopherson, L., 1988: The role of insertions/deletions in the evolution of the intergenic region between psbA and trnH in the chloroplast genome. ? Curr. Genet.14: 137?146.
2. Ball, J., 1873: Descriptions of some new species, subspecies, and varieties of plants collected in Morocco byJ. D. Hooker, G. Maw, andJ. Ball. ? J. Bot.12 (n.s.2): 332?335.
3. , 1878: Spicilegium florae Maroccanae. ? J. Linn. Soc. London16: 281.
4. Battandier, J. A., Trabut, L. C., 1888?1889: Flore del l'Algerie,1. ? Algiers: A. Jourdan.
5. Berger, A., 1930:Crassulaceae. ? InEngler, A., Prantl, K., (Eds): Die natürlichen Pflanzenfamilien, 2nd edn,18 a, pp. 352?483. ? Leipzig: Wilhelm Engelmann.