Cita APA (7th ed.)

Helm, D. (2015). Natural capital: Valuing our planet. Yale University Press.

Cita Chicago (17th ed.)

Helm, Dieter. Natural Capital: Valuing Our Planet. New Haven: Yale University Press, 2015.

Cita MLA (9th ed.)

Helm, Dieter. Natural Capital: Valuing Our Planet. Yale University Press, 2015.