Aprovecho Institute (Cottage Grove, Or.). (1988). Skipping stones. [s.n.].
芝加哥风格引文Aprovecho Institute (Cottage Grove, Or.). Skipping Stones. Cottage Grove, OR: [s.n.], 1988.
MLA引文Aprovecho Institute (Cottage Grove, Or.). Skipping Stones. [s.n.], 1988.
警告：这些引文格式不一定是100％准确.