California Code, Probate Code - PROB § 19152

(a) If a claim is based on a written instrument, either the original or a copy of the original with all endorsements shall be attached to the claim. If a copy is attached, the original instrument shall be exhibited to the trustee on demand unless it is lost or destroyed, in which case the fact that it is lost or destroyed shall be stated in the claim.

(b) If the claim or a part of the claim is secured by a mortgage, deed of trust, or other lien that is recorded in the office of the recorder of the county in which the property subject to the lien is located, it is sufficient to describe the mortgage, deed of trust, or lien and the recording reference for the instrument that created the mortgage, deed of trust, or other lien.