J. S. Frías Ordoñez, D. A. Arjona Granados, and J. D. Martínez Marín, “Vitamin B12 Deficiency in consumption of Metformin and Proton Pump Inhibitors: Déficit de Vitamina B12”, Rev. Médica Risaralda, vol. 28, no. 1, Sep. 2022.