Butterflies of Tamaulipas - Northern Prairie Wildlife Research Center listing of species reported in the state. - http://www.butterfliesandmoths.org/map?dc=5893&_dcc=1
Grutas de Bustamante (Caves of Bustamante) - Overview and links to information about the huge cave system just outside of Bustamante. - http://www.showcaves.com/english/mx/showcaves/Bustamante.html
Gómez Farías Region and El Cielo Biosphere Reserve - Report on geography, flora and fauna, and cultural setting, from Smithstonian Institute's Centres of Plant Diversity. - http://www.nmnh.si.edu/botany/projects/cpd/ma/ma9.htm