J. M. Rodríguez García, S. E. Medina Cuellar, and M. A. Sánchez Jiménez, “Determination of the poverty threshold in Guanajuato: an innovative approach using Engel’s law and the second derivative criterion”, Acta Universitaria, vol. 36, pp. 1–17, Feb. 2026, doi: 10.15174/au.2026.4564.