एपीए उद्धरण

Spencer, E. W. Basic concepts of historical geology.

शिकागो स्टाइल उद्धरण

Spencer, Edgar Winston. Basic Concepts of Historical Geology.

एमएलए उद्धरण

Spencer, Edgar Winston. Basic Concepts of Historical Geology.

चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.