P. Ramírez-Bulla, M. Mercado-Reyes, A. A. Trespalacios-Rangel, J. Avila-Coy, and W. Otero-Regino, “Current status of Helicobacter pylori resistance to tetracycline: a systematic review of the literature”, Universitas Scientiarum, vol. 17, no. 2, pp. 216–229, Jun. 2012.