"HRB" . . "NAE" . . . "Consequences of deferred maintenance" . . . . . . . . . . "Consequences of deferred maintenance : National Cooperative Highway Research Program" . . . . . . . . . . . . . . . . . . "National Research Council (Estats Units d'Amèrica). Transportation Research Board." . . "National Research Council (É.-U.). Transportation Research Board." . . "Roads." . . . . "National Research Council." . . "Straßenunterhaltung." . . "Carreteres Estats Units d'Amèrica Manteniment i reparació." . .