Omnibus Election Code
Section 31. The Sangguniang Pampook of the autonomous regions. - Region IX and Region XII in southern Philippines shall each have a Sangguniang Pampook to be composed of twenty-seven members and shall include seventeen representatives elected from the different provinces and cities of each region, and a sectoral representative each from among the youth, agricultural workers, and non-agricultural workers (industrial labor) of each region to be selected in the manner herein provided whose qualifications and disqualifications are the same as Members of the Batasang Pambansa.
The President shall appoint an additional seven representatives in each region whenever in his judgment any other sector is not properly represented in the Sangguniang Pampook as a result of the elections.