1. 1) H. Horikawa: J. Jpn. Inst. Light Met. 58 (2008) 259–273 (in Japanese).
2. 2) Aluminum Wheel Statistical Data, Japan Aluminium Association, No. 24 (2010) p. 20 (in Japanese).
3. 3) M. Hino, K. Murakami and T. Kanadani: Science and Industry 85 (2011) 12–18 (in Japanese).
4. 4) Y. Kitaoka: J. Jpn. Inst. Light Met. 61 (2011) 485–503 (in Japanese).
5. 5) S. Kawai, H. Kanetsugi, M. Hino and K. Murakami: Japan Patent journal 2010-56677.