Asimov, I. (1983). The caves of steel (1st Ballantine books ed.). Ballantine Books.
芝加哥风格引文Asimov, Isaac. The Caves of Steel. 1st Ballantine books ed. New York: Ballantine Books, 1983.
MLA引文Asimov, Isaac. The Caves of Steel. 1st Ballantine books ed. Ballantine Books, 1983.
警告：这些引文格式不一定是100％准确.