Shepard, P. (1999). Encounters with nature: Essays. Island.
Cita Chicago (17th ed.)Shepard, Paul. Encounters with Nature: Essays. Washington: Island, 1999.
Cita MLA (9th ed.)Shepard, Paul. Encounters with Nature: Essays. Island, 1999.
Atenció: Aquestes cites poden no estar 100% correctes.