Where you should search depends upon your topic.
Image Source: Public Domain. Wikimedia Commons. 1911. Rebel camp, Juarez, Chihuahua, during the Mexican Revolution.
Searching for historical information? Historical Abstracts, Clase Periodica, Arts and Humanities Citation Search, Humanities Source would be best.
Looking for general information on Mexico? A multi-disciplinary source would be best: Academic Search Premier.
Searching for historical information on Mexico/American relations? Try America: History and Life.
Unsure what a scholarly journal article looks like? This Interactive tutorial identifies sections that should appear in a scholarly journal article.