APA (7th ed.) Zitazioa

(2015). one step ahead: Towards environmental sustainability. united nation.

Chicago Style (17th ed.) Zitazioa

One Step Ahead: Towards Environmental Sustainability. cairo: united nation, 2015.

MLA (9th ed.) Zitazioa

One Step Ahead: Towards Environmental Sustainability. united nation, 2015.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.