Aprovecho Institute (Cottage Grove, Or.). (1988). Skipping stones. [s.n.].
Cita Chicago (17th ed.)Aprovecho Institute (Cottage Grove, Or.). Skipping Stones. Cottage Grove, OR: [s.n.], 1988.
Cita MLA (9th ed.)Aprovecho Institute (Cottage Grove, Or.). Skipping Stones. [s.n.], 1988.
Atenció: Aquestes cites poden no estar 100% correctes.