发明授权
US2688005A Cushion for railroad ties comprising a copolymer of styrene and isobutylene, a bituminous material, and a fibrous material 失效
包括苯乙烯和异丁烯的共聚物的铁路连接件,沥青材料和纤维材料

Cushion for railroad ties comprising a copolymer of styrene and isobutylene, a bituminous material, and a fibrous material
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