Civil Code, Art. 1469

In order that the price may be considered certain, it shall be sufficient that it be so with reference to another thing certain, or that the determination thereof be left to the judgment of a special person or persons. Should such person or persons be unable or unwilling to fix it, the contract shall be inefficacious, unless the parties subsequently agree upon the price. If the third person or persons acted in bad faith or by mistake, the courts may fix the price. Where such third person or persons are prevented from fixing the price or terms by fault of the seller or the buyer, the party not in fault may have such remedies against the party in fault as are allowed the seller or the buyer, as the case may be. (1447a)