Não informado. (1981). Soviet Engineering Research. Production Engineering Research Association.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Soviet Engineering Research. Melton Mowbray, Inglaterra: Production Engineering Research Association, 1981.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Soviet Engineering Research. Production Engineering Research Association, 1981.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.