APA

O'Brien J., . (1980). Concentrated traffic enforcement program, Illinois State Police. Springfield,IL: Illinois Department of Transportation. Division of Traffic Safety.

Chicago

O'Brien JP, . 1980. Concentrated traffic enforcement program, Illinois State Police. Springfield,IL: Illinois Department of Transportation. Division of Traffic Safety.

Harvard

O'Brien J., . (1980). Concentrated traffic enforcement program, Illinois State Police. Springfield,IL: Illinois Department of Transportation. Division of Traffic Safety.

MLA

O'Brien JP, . Concentrated traffic enforcement program, Illinois State Police. Springfield,IL: Illinois Department of Transportation. Division of Traffic Safety. 1980.