At head of t.p.: Asiantaeth yr Amgylchedd Cymru, Environment Agency Wales.
See also: Science report [2 parts]: ISBN 9781844327034 / 9781844327041.
Review of lake Benthic macro-invertebrate sampling methods and strategy for the Water Framework Directive. Published by Environment Agency in 2007. Publication and catalogue information, links to buy online and reader comments.