Cal. Pub. Util. Code § 24535

Whenever the signature of any officer or employee of a district or of any member of the retirement board or of any officer or employee of the retirement system is authorized or required under this part, except in the single instance provided in Section 26244, the signature may be made by the use of a plate bearing facsimiles of those signatures or by submittal of a digital signature consistent with Section 16.5 of the Government Code or an electronic signature, as defined in subdivision (h) of Section 1633.2 of the Civil Code.