Fels, R. (1966). An introduction to economics: The challenge to the American economy (2nd ed.). Allyn and Bacon.
芝加哥风格引文Fels, Rendings. An Introduction to Economics: The Challenge to the American Economy. 2nd ed. Boston: Allyn and Bacon, 1966.
MLA引文Fels, Rendings. An Introduction to Economics: The Challenge to the American Economy. 2nd ed. Allyn and Bacon, 1966.
警告：这些引文格式不一定是100％准确.