DGSCA, UNAM, Ciudad Universitaria, Mexico City, 04510 Mexico
Inst. de Ingenieria, UNAM, Apdo. 70-569, Mexico City, 04510 Mexico ; Lab. de Geologie, Dept. TAO, ENS, 24 Rue Lhomond, Paris, 75005 France, Metropolitan
Lab. de Geologie, Dept. TAO, ENS, 24 Rue Lhomond, Paris, 75005 France, Metropolitan