Wallen, R. N. (1992). Introduction to physical geography. WM C. Brown.
芝加哥风格引文Wallen, Robert N. Introduction to Physical Geography. Boulevard: WM C. Brown, 1992.
MLA引文Wallen, Robert N. Introduction to Physical Geography. WM C. Brown, 1992.
警告：这些引文格式不一定是100％准确.