Ar clawr : Canolfan Cenedlaethol Dŵr Daear a Thir Llygredig = On cover : National Groundwater and Contaminated Land Centre.
Teitl clawr = Cover title.
Gosod colofnau mewn safleoedd halogedig. ISBN 1857058046. Published by Environment Agency in 2002. Publication and catalogue information, links to buy online and reader comments.