APA

Hopkins J., White E., . (1977). Improvement of the effectiveness of motorist warnings at railroad-highway grade crossings. Cambridge, MA: U.S. Department of Transportation. Transportation Systems Center. Report nr 76-25.

Chicago

Hopkins JB, White E, . 1977. Improvement of the effectiveness of motorist warnings at railroad-highway grade crossings. Cambridge, MA: U.S. Department of Transportation. Transportation Systems Center. Report nr 76-25.

Harvard

Hopkins J., White E., . (1977). Improvement of the effectiveness of motorist warnings at railroad-highway grade crossings. Cambridge, MA: U.S. Department of Transportation. Transportation Systems Center. Report nr 76-25.

MLA

Hopkins JB, White E, . Improvement of the effectiveness of motorist warnings at railroad-highway grade crossings. Cambridge, MA: U.S. Department of Transportation. Transportation Systems Center. Report nr 76-25. 1977.