Spengler, J. J. (1972). Population economics: Selected essays of Joseph John Spengler. Duke University Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रSpengler, Joseph John. Population Economics: Selected Essays of Joseph John Spengler. Durham, North Carolina: Duke University Press, 1972.
एमएलए (9वां संस्करण) प्रशस्ति पत्रSpengler, Joseph John. Population Economics: Selected Essays of Joseph John Spengler. Duke University Press, 1972.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.