https://www.uexternado.edu.co/ Content Type OA ? PCA ? Books (Back List, Front List) No Yes Request a holdings comparison Portico provides a free holdings comparison service to compare a library’s journal or book holdings to the Portico archive. Search titles and ISSNs by keyword: Show: E-Books All0-9ABCDEFGHIJKLMNOPQRSTUVWXYZ Titles start with U (2) Information Una Visión integral de la seguridad social 3 ED., Ed. 3 Author/Editor: Leonardo Cañón Ortegón Un nuevo concepto de culpa patronal Author/Editor: Diego Alejandro Sánchez Acero