Aldo Leopold, J. Baird Callicott, Eric T. Freyfogle (2001). “For the Health of the Land: Previously Unpublished Essays And Other Writings”, p.189, Island Press
Aldo Leopold (2013). “Aldo Leopold: A Sand County Almanac & Other Writings on Conservation and Ecology: (Library of America #238)”, p.165, Library of America
Aldo Leopold (2013). “Aldo Leopold: A Sand County Almanac & Other Writings on Conservation and Ecology: (Library of America #238)”, p.438, Library of America
Aldo Leopold (2013). “Aldo Leopold: A Sand County Almanac & Other Writings on Conservation and Ecology: (Library of America #238)”, p.315, Library of America
Aldo Leopold (2013). “Aldo Leopold: A Sand County Almanac & Other Writings on Conservation and Ecology: (Library of America #238)”, p.559, Library of America
Aldo Leopold (2013). “Aldo Leopold: A Sand County Almanac & Other Writings on Conservation and Ecology: (Library of America #238)”, p.572, Library of America