1. 1) Ministry of the Environment, Government of Japan: Japan’s Long-term Strategy under the Paris Agreement, (June 11, 2019), https://www.env.go.jp/en/headline/2406.html, (accessed 2020-08-17) (in Japanese).
2. 2) Cabinet Office, Government of Japan: Integrated Innovation Strategy 2019, (June 21, 2019), https://www8.cao.go.jp/cstp/togo2019_honbun.pdf, (accessed 2020-08-17) (in Japanese).
3. 3) M. Takahashi: Tetsu-to-Hagané, 100 (2014), 82 (in Japanese).
4. 4) S. Matsuyama: Tetsu-to-Hagané, 80 (1994), 679 (in Japanese).
5. 5) T. Omura, T. Kushida, T. Kudo, F. Nakasato and S. Watanabe: Zairyo-to-Kankyo, 54 (2005), 61 (in Japanese).