Keyfitz, N., & Flieger, W. (1971). Population: Facts and methods of demography. W. H. Freeman.
芝加哥风格引文Keyfitz, Nathan, 与 Wilhelm Flieger. Population: Facts and Methods of Demography. San Francisco: W. H. Freeman, 1971.
MLA引文Keyfitz, Nathan, 与 Wilhelm Flieger. Population: Facts and Methods of Demography. W. H. Freeman, 1971.
警告：这些引文格式不一定是100％准确.