Avila-Campos, Mario Julio, et al. “ Antimicrobial Resistance and Plasmid Detection in Strains of the Bacteroides Fragilis Group ”. Revista Do Instituto De Medicina Tropical De São Paulo, vol. 35, no. 1, Feb. 1993, pp. 107-10, https://revistas.usp.br/rimtsp/article/view/29005.