Mackie, A. M. (1967). Progress in learning the meanings of symbolic traffic signs. Road Research Laboratory.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रMackie, A. M. Progress in Learning the Meanings of Symbolic Traffic Signs. Crowthorne, Berkshire: Road Research Laboratory, 1967.
एमएलए (9वां संस्करण) प्रशस्ति पत्रMackie, A. M. Progress in Learning the Meanings of Symbolic Traffic Signs. Road Research Laboratory, 1967.
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