California Code
ARTICLE 3 - Proof and Acknowledgment of Instruments
Section 1196.

1196. A witness shall be proved to be a subscribing witness by the oath of a credible witness who provides the officer with any document satisfying the requirements of paragraph (3) or (4) of subdivision (b) of Section 1185.

(Amended by Stats. 2008, Ch. 67, Sec. 2. Effective January 1, 2009.)