American Association of State Highway Officials. (1955). Policy on maintenance of safety and traffic control devices and related traffic services. Amer. Assoc. of State Highway Officials.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रAmerican Association of State Highway Officials. Policy on Maintenance of Safety and Traffic Control Devices and Related Traffic Services. Washington, D.C.: Amer. Assoc. of State Highway Officials, 1955.
एमएलए (8वां संस्करण) प्रशस्ति पत्रAmerican Association of State Highway Officials. Policy on Maintenance of Safety and Traffic Control Devices and Related Traffic Services. Amer. Assoc. of State Highway Officials, 1955.
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