Jirka, I. ESCA Study of Zeolites. In: TRACY, M. M. J., MARCUS, B. K., BISHER, M. E., HIGGINS, J. B., eds. Proceedings of the 12th International Zeolite Conference. Warrendale: Materials Research Society, 1999, s. 2439-2444. ISBN 1-55899-463-7.