7ASTM D790-2007,Standard Test Methods for Flexural Proper- ties of Unreinforced and Reinforced Plastics and Electrical In sulating Materials[S].West Conshohocken,PA.
8AISI. Modern Sewer Design, 4" Edition[M]. American Iron and Steel Institute, 1107 17th Street, N. W. , Suite 1300 Washington, DC, USA: 20036 - 4700,1999.
9CSPI. Handbook of Steel Drainage & Highway Construc- tion Products [M]. Canada Edition, Corrugated Steel Pipe Institute, 2007.
