A preliminary laboratory investigation of passive railroad crossing signs.
APA Citation
Bridwell, N., United States. Federal Highway Administration. Office of Safety and Traffic Operations Research and Development. (1993). A preliminary laboratory investigation of passive railroad crossing signs. McLean, Va.: U.S. Department of Transportation, Federal Highway Administration .
MLA Citation
Bridwell, Nancy, and United States. Federal Highway Administration. Office of Safety and Traffic Operations Research and Development. A Preliminary Laboratory Investigation of Passive Railroad Crossing Signs. McLean, Va.: U.S. Department of Transportation, Federal Highway Administration , 1993.
Warning: These citations may not always be complete (especially for serials).