how currency systems work http://transaction.net/money/index.html

• Michael Linton, inventor of LETS
• LETSystems, http://www.gmlets.u-net.com/
• Openmoney Project http://www.openmoney.org
• “On LETS” by Makoto Nishibe http://www.nam21.org/~overseas/onLETS.html

• “Making Money: Notes on Technology as Environment” http://felix.openflows.org/html/abstract.html
• community currencies http://www.ratical.org/ratitorsCorner/03.20.99.html
• inventions in money during the 1900s http://www.futureofmoneysummit.com/top-10-inventions.php

• currency_converter
• redistribution » http://www.thesimpleway.org/love_dollars/