National Research Council (U.S.). Highway Research Board, Moyer, R. A., Shupe, J. W., & Morgan, A. D. (1951). Roughness and skid resistance: Presented at the Thirtieth Annual Meeting, 1951. Highway Research Board.

National Research Council (U.S.). Highway Research Board, Ralph A. Moyer, John W. Shupe, and A. Duke Morgan. Roughness and Skid Resistance: Presented at the Thirtieth Annual Meeting, 1951. Washington, D.C: Highway Research Board, 1951.

National Research Council (U.S.). Highway Research Board, et al. Roughness and Skid Resistance: Presented at the Thirtieth Annual Meeting, 1951. Highway Research Board, 1951.