http://koha.unicoc.edu.co/cgi-bin/koha/opac-search.pl?q=ccl=%28su%3A%22Teor%C3%ADa%20del%20derecho%22%29%20and%20au%3AKelsen%2C%20Hans%2C&format=rss2 Search results for '(su:"Teoría del derecho") and au:Kelsen, Hans,' at SIBU - SISTEMAS DE BIBLIOTECAS UNICOC 0 20