See Part II: The Current Debate: How Electricity Works at the Atomic Level under July 2010 heading
Part III The Current Debate: The Electro-Chemical Impulses of the Body
Hockenbury,D.H., Hockenbury, S.E., (2010) Psychology 5th Edition. Worth Publishers: NY, New York.
Physics: Electric Current Through Various Media Downloaded July 2, 2010 from Wikipedia at http://en.wikipedia.org/wiki/Electric_current