Recommended health-based limits in occupational exposure to heavy metals: Technical WHO-Report 647 of a WHO study group (Chairman: Professor R.L. Zielhuis, University of Amsterdam) in English, French and Spanish, 1980, 116 pages, no index, many valuable literature references added to each chapter, stiff paper cover, format 200 × 140 mm, ISBN 92-4-120647-G, WHO-Health & biomedical information programme, CH-1211 Geneva 27, SFr. 8.-