Statement of Copyright
Copyright © 2012 All rights reserved.
American Journal of Physics is copyrighted. Individual articles in American Journal of Physics are copyrighted by the society, as indicated on each article.
Individual articles may be downloaded for personal use; users are forbidden to reproduce, republish, redistribute, or resell any materials from this journal in either machine-readable form or any other form without permission of the society or payment of the appropriate royalty for reuse.