Many states based their laws governing corporations on the Model Business Corporations Act, which was first approved by the American Bar Association (ABA) in 1950. This act was significantly revised by the ABA in 1969 and again in 1984. A second popular source for corporation laws is the Delaware General Corporation Law. Delaware has a history of legislation that is particularly friendly to corporations, and so many corporations historically have chosen to incorporate there (see below). Lastly, the American Law Institute has produced Principles of Corporate Governance: Analysis and Recommendations, which courts often rely upon when ruling on matters related to the conduct of a business corporation.