阀门标准 BS EN 558-2-1996 Industrial valves — Face-to-face and centre-to-face dimensions of metal.pdf [db:摘要]
阀门标准 BS EN 13959-2004 Anti-pollution check valves – —N 6 to —N 250 inclusive Family E, type A, B, C, and —.pdf [db:摘要]
