2 WHO Library Cataloguing-in-Publication Data Bonita Ruth. Basic epidemiology / R. Bonita R. Beaglehole T. Kjellström. 2nd edition. 1.Epidemiology. 2.Manuals. I.Beaglehole Robert. II.Kjellström Tord. III.World Health Organization. ISBN 92 4 154707 3 NLM classification: WA 105 ISBN 978 92 4 154707 9 © World Health Organization 2006 All rights reserved. Publications of the World Health Organization