Prem H. NAASRA roughness meter calibration via the road-profile-based international roughness index (IRI) / H. Prem, 1989. - 35 p. - Текст : непосредственный.
literature study of pavement user ratings / P.T.Cairney,H.Prem,J.R.McLean,D.W.Potter, 1989. - 21 p. - Текст : непосредственный.