Copper’s role in the green economy
http://www.ideabookclub.com/index.php?action=profile;u=76928

How to calculate electric conductivity of copper?
http://arabfm.net/vb/showthread.php?p=3958249#post3958249


A Great Copper Squeeze Is Coming for the Global Economy
http://www.voteup.club/showthread.php?tid=68&pid=257#pid257

Copper Wire Types
http://2xianqiao.com/forum.php?mod=viewthread&tid=952&page=1&authorid=379

The different types of bare copper conductors
http://www.101skins.com.tw/forum.php?mod=viewthread&tid=2970587&extra=

What are some best practices for copper electrical connectors?
http://www.filateelia.ee/foorum/viewtopic.php?t=8700