California Code, Government Code - GOV § 43820

In its ordinance or resolution authorizing the issuance of bonds, a city legislative body may provide that a certain portion of such bonds, as determined and specified in the ordinance or resolution, will be paid by the city each year prior to maturity, at the option of the holders, pursuant to this article.  Such advance payment of bonds shall be in addition to the payment of bonds of the same issue at maturity.