"National Hispanic Heritage Month is a national observance authorized by Public Law 100-402. The observation was initiated in 1968 as National Hispanic Heritage Week but was expanded in 1988 to include the entire 31 day period." http://www.nea.org/takenote/hispanherit0509.html
See also http://www.infoplease.com/spot/hhm1.html
Bases de Datos de Ebsco-Ehostes y Thomson Gale-Informe
(Virtual Reference Collection)
http://esboces.org/SLS/vrc.cfm?uCol=23