\documentclass[12pt,letterpaper]{article}\usepackage[latin1]{inputenc}\usepackage[spanish]{babel}\usepackage{amsmath}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{graphicx}\usepackage[left=4cm,right=2cm,top=3cm,bottom=3cm]{geometry}\author{ALEXANDER GMEZ MEJA\\ \\ \\ \\ \\ \\ \\POR: Aquiles Clavo\\ \\ \\ \\ \\ \\ \\ UNIVERSIDAD NACIONAL DE COLOMBIA\\FACULTAD DE INGENIERA \\DEPARTAMENTO DE INGENIERA MECNICA Y MECATRNICA \\ BOGOT D.C. \\ }\title{SISTEMAS DE INVESTIGACIN}\date{2015-03-13}\renewcommand{\baselinestretch}{1.5}\begin{document}\maketitleBibliografa \\ \begin{itemize}\item $http://www.pnud.org.co/sitio.shtml?apc=i1-----s=am=ae=Bc=02008.VQIuJY6G_4Y$\item http://ccqc.pangea.org/cast/sosteni/soscast.htm\item http://problemassocialesdecolombia.blogspot.com/\item http://www.cna.gov.co/1741/article-187381.html\item http://www.banrepcultural.org/blaavirtual/economia/industrilatina/088.htm\item http://www.gestiopolis.com/recursos/documentos/fulldocs/eco/detyc.htm\end{itemize} \end{document}