Cita APA (7a ed.)

Orr, D. W. (2011). Hope is an imperative: The essential David Orr. Island Press.

Cita Chicago Style (17a ed.)

Orr, David W. Hope Is an Imperative: The Essential David Orr. Washington, DC: Island Press, 2011.

Cita MLA (9a ed.)

Orr, David W. Hope Is an Imperative: The Essential David Orr. Island Press, 2011.