Cal. Lab. Code § 1287

If upon inspection or investigation the director determines that a person is in violation of any statutory provision or rule or regulation relating to the employment of minors, he may issue a citation to the person in violation. The citation may be served personally or by registered mail in accordance with subdivision (c) of Section 11505 of the Government Code. Each citation shall be in writing and shall describe the nature of the violation, including reference to the statutory provisions, rule, or regulation alleged to have been violated.