BUDLONG MO. (1998). TEACH YOURSELF COBOL IN 21 DAYS (2ND.). TECHMEDIA.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रBUDLONG MO. TEACH YOURSELF COBOL IN 21 DAYS. 2ND. NEW DELHI: TECHMEDIA, 1998.
एमएलए (9वां संस्करण) प्रशस्ति पत्रBUDLONG MO. TEACH YOURSELF COBOL IN 21 DAYS. 2ND. TECHMEDIA, 1998.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.