Clay Shaw and CIA activities

Much has been written and speculated on about Shaw's activities on behalf of, or in association with the Central Intelligence Agency. Other than Shaw's contacts from 1948-56, which have been officially acknowledged, and had to do with answering questions about his travels to Central and South America, and the Caribbean, and other minor giving of information, what do you maintain Shaw did for the CIA, and what is the source of your information (official CIA document, published book or article, etc.)?