Long-Term Observation of the Geological Environment : Needs and Techniques. Disposal of Radioactive Waste. Proceedings of an NEA Workshop Helsinki, Finland 9-11 September 1991. OECD Documents. 1. ed. Paris : OECD, 1993. 214 s. ISBN 92-64-03970-8. [Copy count : 1, currently available 1, at library only 0]