1. 1) Hare, C. M. and O’Loughlin, G. G. : An algorithm for pressure head change coefficients at stormwater manholes, in Urban Drainage and New Technologies (UDI’91), Dubrovnik, Elsevier, London, 1991.
2. 2) Stein, S. M., Dou, X., Umbrell, E. R. and Jones, J. S. : Stormsewer junction hydraulics and sediment transport, US Federal Highway Administration Turner-Fairbanks Highway Research Centre, VA (available on www.tfhrc.gov/structr/hydrlcs/pdf/3.pdf), 1999.
3. 3) U.S. Department of Transportation? Federal Highway Administration, Urban Drainage Design Manual, Hydraulic Engineering Circular No. 22, Third Edition, Office of Engineering, Office of Technology Applications, Washington, DC, 2009.
4. 4) Ryu, T. H., Kim, J. S. and Yoon, S. E. : An experimental study for estimation of head loss coefficients at surcharged four-way combining manholes, J. Korea Water Resour. Assoc., Vol. 49, No. 12, pp. 1015-1025, 2016.
5. 5) Jo, J. B., Kim, J. S. and Yoon, S. E.：Development of head loss coefficient formula at surcharged four-way combining square manhole with variation of inlet flow, J. Korea Water Resour. Assoc., Vol. 50, No. 12, pp. 877-887, 2017.