1. K. Tanabe, M. Misono, Y. Ono, H. Hattori, New Solid Acids and Bases, Kodansha, 1990.
2. Y. Ogino, Shokubaikougaku Koza, Catalytic Engineering Series: in: T. Shiba (Ed.), vol. 9, Chijinshokan, Tokyo, 1966, p.127.
3. Y. Izumi, Shokubai Koza, Catalyst Series: in: T. Onoda, K. Tamaru, M. Misono, Y. Morooka (Eds.), vol. 8, Kodansha Scientific, 1985, p.275.