Celia Maqueda, Agua Santas Romero, Esmeralda Morillo, Jose L. Perez-rodriguez, Anton Lerf, Friedrich Ernst Wagner: The behavior of Fe in ground and acid-treated vermiculite from Santa Olalla, Spain. 2008Clays and Clay Minerals: 56. ISBN 0009-8604 http://dx.doi.org/10.1346/CCMN.2008.0560307