Code of Organization and Civil Procedure (Cap. 12), article 675

675. Where the subject-matter of t he reference is a valuation or an assessment, it shall be lawfu l for the court, in either of t he cases referred to in the last preceding article, on the demand of any of the parties, to appoint two additiona l referees; and upon their rep ort, to fix an average of the amounts f ound in all the disagreeing repo rts. When additional referee cannot be appointed.