Leal, Nilma Cintra, et al. “ Plasmid Composition and Virulence-Associated Factors of Yersinia Pestis Isolates from a Plague Outbreak at the Paraíba State, Brazil ”. Revista Do Instituto De Medicina Tropical De São Paulo, vol. 31, no. 5, Oct. 1989, pp. 295-00, https://www.revistas.usp.br/rimtsp/article/view/28679.