APA

Transportation Research Record 2122, . (2009). Traffic control devices, visibility, and highway-rail grade crossings 2009. Washington DC: Transportation Research Record 2122.

Chicago

Transportation Research Record 2122, . 2009. Traffic control devices, visibility, and highway-rail grade crossings 2009. Washington DC: Transportation Research Record 2122.

Harvard

Transportation Research Record 2122, . (2009). Traffic control devices, visibility, and highway-rail grade crossings 2009. Washington DC: Transportation Research Record 2122.

MLA

Transportation Research Record 2122, . Traffic control devices, visibility, and highway-rail grade crossings 2009. Washington DC: Transportation Research Record 2122. 2009.