1. 2) Mizumoto, K.;Yamaguchi, K.: “Gomu Kanagata Gijutsu”, Posty Corporation, Tokyo, p.85 (2014)
2. 5) Nishizawa, N.: “Gomu Kanagata Gijutsu”, Posty Corporation, Tokyo, p.45 (2014)
3. 8) Yamaguchi, K.: “Gomu Kanagata Gijutsu”, Posty Corporation, Tokyo, p.173 (2014)