•
http://www.physicsonstage.com
•
http://www.aps.org
•
http://www.aps.org/centennial/
•
http://www.aapt.org
•
http://www.cdtl.nus.edu.sg
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http://xcalibre.ac.uk
•
http://pwista.com/
•
http://www.aapt.org/Projects/ntfup.cfm (SPIN-UP)
•
http://www.iop.org/
•
http://www.physicscentral.com/
•
http://www.phystec.org/
•
http://www.physics2005.org/
http://galileo.harvard.edu
http://webphysics.ph.msstate.edu/jc/library/index.htm
http://www.howstuffworks.com/
http://howthingswork.virginia.edu/
