3G Weib, H Brombach, Haller. Infiltration and inflow in combined sewer system: long-term analysis [J]. Water Sic &Tech, 2002, 47(7): 11-19.
4Stephen E Cordes, Graham Knott, Arun K Deb, et al. Existing sewer evaluation & rehabilitation [M]. American: Water Envi ronment Federation, 1994. 71-71.