Terms of Use

In order to purchase and download a PDF file, a customer must agree to the Terms of Use for the National Academies Press Electronic Publications, as detailed below.


The National Academy of Sciences, a private nonprofit corporation chartered by an act of Congress, and the organizations formed under its congressional charter, the National Academies Press, National Academy of Engineering, Institute of Medicine, and National Research Council are collectively referred to herein as the "National Academies."


The National Academies owns all rights in the electronic publications and the copyrights therein displayed on this website (Online Publications). Copyright National Academy of Sciences. All rights reserved.

PDF Files: Copying and Distributing

Users of this website who accept and agree to the conditions specified in these Terms of Use (Authorized Users) may print single copies in PDF format of the Online Publications solely for their personal noncommercial use in accordance with the terms of this Agreement. Substantial or systematic reproduction by Authorized Users is not permitted. Distributing or posting the PDF files is strictly prohibited without written permission of the NAP. Use of the Online Publications constitutes Authorized User's agreement with these terms.

Alteration; Notices

Authorized Users may not modify, adapt, transform, translate or create any derivative work based on any materials included in the Online Publications, or otherwise use any such materials in a manner that would infringe the copyrights therein. Each PDF file of an Online Publication will include a Copyright Notice and unique tracking number specific to the Authorized User. The copyright notice, confirmation number, and any other notices or disclaimers may not be removed, obscured, or modified in any way.


The National Academies and its officers, employees, and agents do not accept any legal responsibility for errors, omissions or claims, nor do they provide any warranty, express or implied, with respect to information published in the Online Publications. In no event shall the National Academies be liable for any special, indirect, or consequential damages. THE NATIONAL ACADEMIES EXPRESSLY EXCLUDES ANY LIABILITY FOR BREACH OF ANY IMPLIED OR EXPRESS WARRANTY AS TO MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

User Warranties

Each Authorized User warrants that it will use reasonable efforts to ensure the security and integrity of each Electronic Publication, and will notify the National Academies promptly of any unauthorized use of the Online Publication of which they become aware. Any abuse of these Terms of Use will result in immediate cessation of access to National Academies servers and may be pursed to the fullest extent permitted under applicable laws, treaties, and conventions.

Change of Terms

The National Academies reserves the right to change, modify, or otherwise alter the terms of this license without prior notice to the Authorized User.

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