Dyfyniad APA

(1996).  Sustainability, the environment and urbanization.  Earthscan.

Dyfyniad Arddull Chicago

 Sustainability, the Environment and Urbanization.  Earthscan, 1996.

Dyfyniad MLA

 Sustainability, the Environment and Urbanization.  Earthscan, 1996.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.