ECA: Estudios Centroamericanos. “La encíclica ‘Populorum Progessio’ De Paulo IV”. ECA: Estudios Centroamericanos 22, no. 227 (June 30, 1967): 475–476. Accessed January 14, 2026. https://revistas.uca.edu.sv/index.php/eca/article/view/10535.