http://martinfowler.com/articles/richardsonMaturityModel.html

What is REST? http://roy.gbiv.com/untangled/2008/rest-apis-must-be-hypertext-driven , in short, it should not limit to web and http

http://stackoverflow.com/questions/671118/what-exactly-is-restful-programming

http://www.infoq.com/articles/api-business-models