Não informado. (1966). Summary of progress. National Cooperative Highway Research Program.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Summary of Progress. Washington: National Cooperative Highway Research Program, 1966.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Summary of Progress. National Cooperative Highway Research Program, 1966.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.