Santayana. The Life of Reason or The Phases of Human Progress. The MIT Press.
芝加哥风格引文Santayana. The Life of Reason or The Phases of Human Progress. The MIT Press.
MLA引文Santayana. The Life of Reason or The Phases of Human Progress. The MIT Press.
警告：这些引文格式不一定是100％准确.