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NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.

This study was supported by the National Institute of Standards and Technology under contract No. SB134106Z0011. The opinions, findings, and conclusions or recommendations contained in this document are those of the authors and do not necessarily reflect the views of the National Institute of Standards and Technology.

International Standard Book Number-13: 978-0-309-18677-3
International Standard Book Number-10: 0-309-18677-3
Library of Congress Control Number: 2011933648

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