Une, Clas, Wendy Malespín Bendaña, Vanessa Ramírez-Mayorga, Luis Rosero Bixby, and Rafaela Sierra Ramos. 2022. “Helicobacter Pylori Infection and Serum Pepsinogen Concentrations in an Elderly Population Representative of Costa Rica”. Población Y Salud En Mesoamérica 19 (2). https://doi.org/10.15517/psm.v19i2.49405.