Designations used by companies to distinguish their products are often claimed as trademarks. In all instances where John Wiley Sons, Inc, is aware of a claim, product names appear in initial capital or ALL CAPITAL LETTERS. Readers, however, should contact the appropriate companies for more complete information regarding trademarks Copyright 2001 by Wiley-Liss, Inc. All rights reserved No part of this publication may be reproduced, stored in a retrieval system or ransmitted in any form or by any means, electronic or mechanical, including uploading downloading, printing, decompiling, recording or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without the prior written permission of the Publisher. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley Sons, Inc, 605 Third Avenue New York,NY10158-0012,(212)850-6011,fax(212)850-6008, EMail: PERMREOOWILEY. COM. This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold with the understanding that the publisher is not engaged in rendering professional services. If professional advice or other expert assistance is required, the services of a competent professional person should be sought. ISBN0-471223905 This title is also available in print as ISBN 0-471-37972-7 For more information about Wiley products, visit our web site atDesignations used by companies to distinguish their products are often claimed as trademarks. In all instances where John Wiley & Sons, Inc., is aware of a claim, the product names appear in initial capital or all capital letters. Readers, however, should contact the appropriate companies for more complete information regarding trademarks and registration. Copyright © 2001 by Wiley-Liss, Inc. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic or mechanical, including uploading, downloading, printing, decompiling, recording or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without the prior written permission of the Publisher. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 605 Third Avenue, New York, NY 10158-0012, (212) 850-6011, fax (212) 850-6008, E-Mail: PERMREQ@WILEY.COM. This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold with the understanding that the publisher is not engaged in rendering professional services. If professional advice or other expert assistance is required, the services of a competent professional person should be sought. ISBN 0-471-22390-5 This title is also available in print as ISBN 0-471-37972-7. For more information about Wiley products, visit our web site at www.Wiley.com