2Takatsugu Hasimoto, Kodaira. High Aromatic Oil and Rubber Composition and Oil Extened Synthetic Rubber U- sing the Same[P]. USA:USP 006103808 A,2000-08-15.
6Takatsugu Hasimoto, Kodaira. High aromatic oil and rubber composition and oil extened synthetic rubber using the same: US, 006103808 A[P]. 2000-08-15.