Wide dispersal and possible multiple origins of low-copy-number plasmids in Rickettsia species associated with blood-feeding arthropods - Baldridge, G. D; Burkhardt, Nicole Y; Labruna, Marcelo Bahia; Pacheco, Richard de Campos; Paddock, Christopher D; Williamson, Philip C; Billingsley, Peggy M; Felsheim, Roderick F; Kurtti, Timothy. J; Munderloh, Ulricke G (Applied and Environmental Microbiology, 2010)