Section 309.90 - What governing Tribal law or regulations must a Tribe or Tribal organization include in a Tribal IV-D plan?(a) A Tribe or Tribal organization must include in its Tribal IV-D plan Tribal law, code, regulations, and/or other evidence that provides for: (1) Establishment of paternity for any child up to and including at least 18 years of age;(2) Establishment and modification of child support obligations;(3) Enforcement of child support obligations, including requirements that Tribal employers comply with income withholding as required under § 309.110 ; and(4) Location of custodial and noncustodial parents.(b) In the absence of written laws and regulations, a Tribe or Tribal organization may provide in its plan detailed descriptions of any Tribal custom or common law with the force and effect of law which enables the Tribe or Tribal organization to satisfy the requirements in paragraph (a) of this section.