1. Highway Capacity Manual, Bureau of Public Roads, U.S. Government Printing Office, Washington DC (1950)
2. Highway Capacity Manual, Special Report 87, Transportation Research Board, Washington DC (1965)
3. Highway Capacity Manual, Special Report 209, Transportation Research Board, Washington DC (1985)
4. Messer, C.J.: Two-Lane, Two-Way Rural highway Level of Service and Capacity Procedures. Project Report, NCHRP Project 2-38A, Texas Transportation Institute, Texas A & M University, College Station, TX (February 1983)
5. Messer, C.J.: Two-Lane, Two-Way Rural Highway Capacity. Final Report, NCHRP Project 2-38A, Texas Transportation Institute, Texas A & M University, College Station, TX (February 1983)