Spengler, J. J. (1972). Population economics: Selected essays of Joseph John Spengler. Duke University Press.
芝加哥风格引文Spengler, Joseph John. Population Economics: Selected Essays of Joseph John Spengler. Durham, North Carolina: Duke University Press, 1972.
MLA引文Spengler, Joseph John. Population Economics: Selected Essays of Joseph John Spengler. Duke University Press, 1972.
警告：这些引文格式不一定是100％准确.