Philip, C. B. "Comments on the classification of the order Rickettsiales. " Can. J. Microbiol. (1956) 2:261-270.
The Global Biodiversity Information Facility:
GBIF Backbone Taxonomy, 2013-07-01.
Accessed via http://www.gbif.org/species/3223030 on 2015-03-05
This backbone name usage exists because it was found in another checklist at the time the backbone was built. The primary source name usage has since been removed from the portal.