National Research Council (U.S.). Highway Research Board. (1957). Pavement condition surveys: Suggested criteria. Highway Research Board.
Cita Chicago (17th ed.)National Research Council (U.S.). Highway Research Board. Pavement Condition Surveys: Suggested Criteria. Washington, D.C: Highway Research Board, 1957.
Cita MLA (9th ed.)National Research Council (U.S.). Highway Research Board. Pavement Condition Surveys: Suggested Criteria. Highway Research Board, 1957.
Atenció: Aquestes cites poden no estar 100% correctes.