Universidad Pedagógica Nacional Unidad Ajusco Catálogo de la Biblioteca "Gregorio Torres Quintero"
by Convention concerning the protection of the world cultural and natural heritage (18a. : 1994 : Thailand).
by Convention concerning the protection of the world cultural and natural heritage (19a. : 1995 : Berlin, Germany).
by Convention concerning the protection of the world cultural and natural heritage (20a. : 1996 : Merida, México).