Stackebrandt (1988). "Proteobacteria classis nov., a Name for the Phylogenetic Taxon That Includes the "Purple Bacteria and Their Relatives"". International Journal of Systematic Bacteriology. 38 (3): 321-325. doi:10.1099/00207713-38-3-321. ISSN0020-7713.
Stackebrandt (1988). "Proteobacteria classis nov., a Name for the Phylogenetic Taxon That Includes the "Purple Bacteria and Their Relatives"". International Journal of Systematic Bacteriology. 38 (3): 321-325. doi:10.1099/00207713-38-3-321. ISSN0020-7713.