Harland, W. B. (1989). A geologic time scale 1989. Cambridge University Press.
芝加哥风格引文Harland, Walter Brian. A Geologic Time Scale 1989. New York: Cambridge University Press, 1989.
MLA引文Harland, Walter Brian. A Geologic Time Scale 1989. Cambridge University Press, 1989.
警告：这些引文格式不一定是100％准确.