Encíclicas y documentos pontificios. 

 - Oviedo  Consejo Diosesano de los Hombre de Acción Católica  1964 
 - 632 p. 
 - Doctrina social de la iglesia. .
<br/><br/> Translation made up from various sources. 
<br/><br/>Rerum Novarum, by Leo XIII.--Quadragesimo Anno, by Pius XI.--Divinis Redemptoris, by Pius XI.--Mater et Magistra, by Joannes XXIII.--Diuturnum, by Leo.