Share Email Facebook Twitter LinkedIn References The articles or documents that are referred to in this on-line help are listed below. Please click on the desired link to reveal related information. Topics in this section Culvert Design Manual (1997) Explanatory Note for FD2320 and FD2321 FD2320/TR2 FD2321/TR1 Gomez, M. and Russo, B. (2011) Ramsbottom D., May R., and Rickard C. (1996) Urban Drainage Design Manual (2009) WRC (1986)