 Technically, the Court of Appeal is obligated to publish any opinion that materially contributes to the development of California caselaw, but this rule is not strictly followed, and the Court of Appeal often fails to publish opinions until a party submits a request to that effect.Legal treatises are one of the most important sources of secondary authority about California law.These texts are expressly recognized as a source of 'unwritten law' by California's Code of Civil Procedure.