Cal. Code of Civil Procedure - CCP § 2020.010. Section 2020.010.
(a)
Any of the following methods may be used to obtain discovery within the state from a person who is not a party to the action in which the discovery is sought:
(1)
An oral deposition under Chapter 9 (commencing with Section 2025.010).
(2)
A written deposition under Chapter 11 (commencing with Section 2028.010).
(3)
A deposition for production of business records and things under Article 4 (commencing with Section 2020.410) or Article 5 (commencing with Section 2020.510).
(b)
Except as provided in subdivision (a) of Section 2025.280, the process by which a nonparty is required to provide discovery is a deposition subpoena.
