Gutiérrez-Jiménez, Javier, et al. “Virulence Genes and Resistance to Antibiotics of Beta-Hemolytic Streptococci Isolated from Children in Chiapas, Mexico”. The Journal of Infection in Developing Countries, vol. 12, no. 02, Feb. 2018, pp. 80-88, doi:10.3855/jidc.9679.