Cal. Pub. Util. Code § 90507

The agreements and leases shall be duly acknowledged before a person authorized by law to take acknowledgments of deeds and in the form required for acknowledgment of deeds. The agreements, leases, and equipment trust certificates shall be authorized by resolution of the district and shall contain such covenants, conditions and provisions as may be deemed necessary or appropriate to insure the payment of the equipment trust certificates from the revenue or income to be derived from the transit system.