California Code
ARTICLE 4 - Tangible Personal Property
Section 21636.6.

21636.6. It is unlawful for any person, who is required to be licensed under Section 21640, to publicly advertise any matter relating to the business for which the license is required without including the license number.

(Added by Stats. 1992, Ch. 647, Sec. 3. Effective January 1, 1993.)