California Codes, Civil Code - CIV, Division 2 — Property, Part 3 — Personal or Movable Property, Title 2 — Particular Kinds of Personal Property, Chapter 3 — Products of the Mind, Section 981
(a) Unless otherwise agreed, an original work of authorship not fixed in any tangible medium of expression and in the creation of which several persons are jointly concerned, is owned by them in equal proportion.
(b) Unless otherwise agreed, an invention or design in the production of which several persons are jointly concerned is owned by them as follows:
(1) If the invention or design is single, in equal proportions.
(2) If it is not single, in proportion to the contribution of each.
Notes
Sets joint ownership of an unfixed original work equally among the persons jointly involved in its creation unless they agree otherwise. Joint creators of a single invention or design likewise own equal shares unless otherwise agreed; if the invention or design is not single, ownership follows each person’s contribution, absent a different agreement.
Use as reference
Lexinter.net | California Code, Civil Code - CIV § 981 | https://laws.lexinter.net/codes/california/civil-code/division-2/part-3/title-2/chapter-3/section-981