California Code, Government Code - GOV § 75583

(a) Any judge retired pursuant to this chapter who is appointed by the Supreme Court or any court of appeal, or division thereof, to act as a master or referee in any proceeding pending before any such court or before the Commission on Judicial Performance, shall be paid while so acting, in addition to his or her retirement allowance (taken without reduction on account of any election pursuant to Article 6 (commencing with Section 75570)) the difference, if any, between the retirement allowance and the compensation of a judge of the court from which he or she retired.

(b) When appointed to act as referee in a county other than that in which he or she resides, he or she shall also be allowed his or her necessary expenses for travel, board, and lodging incurred in the discharge of that appointment.

(c) The extra compensation and expenses, if any, shall be chargeable to the state.