Land Grants

Does anybody know how to obtain copies of land grants given to the Espanoles in Mexico? I know I descend from several HAcendados from old Mexico, but im most interested in the land grant made on Feb 17, 1899 in Huanusco, Zacatecas. They have an original copy at the Hacienda de la Luz where my moms side of the family owned. The Camino family. My 3rd great grandfather Mariano Camino b. 1853 owned HAcienda de la Luz from 1899 to his death in 1915. Then his son (my 2 great grand uncle) suceeded him as the next Hacendado his name was Manuel Camino (b. 1878). He only had the hacienda for two years. (1915-1917). In 1917 is when my grandfather says the Mexican gov't abolished all the HAcendados, Haciendas, and made all the land under the control of the govt. Prior to 1917 the Haciendas were "self" governed by representation of the HAcendado on behalf of the gov't. I would also like to obtain other land grants for other haciendad their family owned. Hacienda La Labor en Calvillo, Ags. I was thinking it might be in the Archivo General de la Nacion, but not sure where to look. Only one child of Mariano was actually born on the hacienda which was Amilia Camino (b. 1899) when the hacienda was officially established. Does anyone have any advice? Thanks a lot. Any help is appreciated. -Daniel Mendez del Camino