Code of Civil Procedure CCP § 94
Discovery is permitted only to the extent provided by this section and Section 95 . This discovery shall comply with the notice and format requirements of the particular method of discovery, as provided in Title 4 (commencing with Section 2016.010 ) of Part 4. As to each adverse party, a party may use the following forms of discovery:
(a) Any combination of 35 of the following:
(1) Interrogatories (with no subparts) under Chapter 13 (commencing with Section 2030.010 ) of Title 4 of Part 4.
(2) Demands to produce documents or things under Chapter 14 (commencing with Section 2031.010 ) of Title 4 of Part 4.
(3) Requests for admission (with no subparts) under Chapter 16 (commencing with Section 2033.010 ) of Title 4 of Part 4.
(b) One oral or written deposition under Chapter 9 (commencing with Section 2025.010 ), Chapter 10 (commencing with Section 2026.010 ), or Chapter 11 (commencing with Section 2028.010 ) of Title 4 of Part 4. For purposes of this subdivision, a deposition of an organization shall be treated as a single deposition even though more than one person may be designated or required to testify pursuant to Section 2025.230 .
(c) Any party may serve on any person a deposition subpoena duces tecum requiring the person served to mail copies of documents, books, or records to the party’s counsel at a specified address, along with an affidavit complying with Section 1561 of the Evidence Code .
The party who issued the deposition subpoena shall mail a copy of the response to any other party who tenders the reasonable cost of copying it.
(d) Physical and mental examinations under Chapter 15 (commencing with Section 2032.010 ) of Title 4 of Part 4.
(e) The identity of expert witnesses under Chapter 18 (commencing with Section 2034.010 ) of Title 4 of Part 4.