As Q pointed out, Rafael Hernández was not Mexican - but I hate to separate an answer from a request. He was a Puerto Rican who moved to New York, but his music is popular in all Latin countries. There is a more detailed biography (with sound clips) at http://www.musicofpuertorico.com. Hernández was born in Puerto Rico in 1892, and died in 1965. This page is a collection of MIDI transcriptions of his music.
-Joe Offer-