Walker, William, 1946- Fissile material stocks : characteristics, measures and policy op tions / by William Walker and Frans Berkhout. - New York : United Nations, 1999. - x, 60 p. : ill. ; 21 cm. "UNIDIR/99/8." Includes bibliographical references. ISBN: 9290451319 Subjects--Topical Terms: Radioactive substances --Storage.------Plutonium.--Security measures.------Uranium.--------Reactor fuel reprocessing --------Nuclear nonproliferation.--------