Pettingill, O. S. (1965). The bird watcher's America. McGraw-Hill Book Co., Inc.
芝加哥风格引文Pettingill, Olin Sewall. The Bird Watcher's America. New York: McGraw-Hill Book Co., Inc, 1965.
MLA引文Pettingill, Olin Sewall. The Bird Watcher's America. McGraw-Hill Book Co., Inc, 1965.
警告：这些引文格式不一定是100％准确.