1. Arai Y. Material chemistry of cement. Dainihon publishing, Tokyo, 1986, p. 209–222.
2. European Environment Agency. Waste generation and management —Environment in EU at the turn of century, Euro. Environ. Agen. Press, Copenhagen, Denmark, 1999, p. 212–213.
3. Environmental degradation caused by chemical weapon;Kikuchi;Chem. Ind.,1999
4. Kurita T. International comparison 1998. Japan institute for social and economic affairs, Tokyo, 1997. p. 78–79.
5. Machinery and Industry Association of Japan. The 1998 report on environmental trends, Tokyo, 1999. p. 9–13.