California Code, Revenue and Taxation Code - RTC § 610

(1) A certified copy of a deed, judgment, or other instrument that creates or legally verifies that person's ownership interest in the property.

(2) A certified copy of a document creating that person's security interest in the property.

(3) His or her declaration, under penalty of perjury, that he or she currently has possession of the property and intends to be assessed for the property in order to perfect a claim in adverse possession.