1. Y. S. Lee, S.G. Lee and J. S. Kim, Korean Chem. Eng. Res, 33, 46 (1995).
2. Y. S. Lee, M. G. Kim and Y. Kato, Korean Chem. Eng. Res, 39, 536 (2001).
3. S. Hiraoka, Y. Tada, Y. Kato, A. Matsuura, T. Yamaguchi and Y. S. Lee, J. Chem. Eng. Japan, 34, 1499 (2001).
4. Y. S. Lee and Y. Kato, J. Korean Ind. Eng. Chem., 16, 698 (2005).
5. R. Ohmasa, Kagaku Souchi, 36, 100 (1994).