1. 1) Y. Okuda: Petrotech, 16 (1993) , 300-306.
2. 3) M. Sato: J. Jpn. Inst. Energy, 80 (2001) , 1064-1074.
3. 4) MH21 Research Consortium:http://www.mh21japan.gr.jp/japanese/index.html
4. 5) T. Fujii, T. Saeki, T. Kobayashi, T. Inamori, M. Hayashi, O. Takano, T. Takayama, T. Kawasaki, S. Nagakubo, M. Nakamizu and K. Yokoi: Offshore Technology Conf., (Houston, 2008) , OTC 19310.