Schaeffer, F. A., & Koop, C. E. (1980). Whatever happened to the human race? Marshall, Morgan & Scott.
芝加哥风格引文Schaeffer, Francis A., 与 Charles Everett Koop. Whatever Happened to the Human Race? London: Marshall, Morgan & Scott, 1980.
MLA引文Schaeffer, Francis A., 与 Charles Everett Koop. Whatever Happened to the Human Race? Marshall, Morgan & Scott, 1980.
警告：这些引文格式不一定是100％准确.