National Research Council (U.S.). Transportation Research Board. (1990). Research problem statements: Operation, safety and maintenance of transportation facilities. Transportation Research Board, National Research Council.
Chicago-viite (17. p.)National Research Council (U.S.). Transportation Research Board. Research Problem Statements: Operation, Safety and Maintenance of Transportation Facilities. Washington, D.C: Transportation Research Board, National Research Council, 1990.
MLA-viite (9. p.)National Research Council (U.S.). Transportation Research Board. Research Problem Statements: Operation, Safety and Maintenance of Transportation Facilities. Transportation Research Board, National Research Council, 1990.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.