28 U.S.C. § 2108 : US Code - Section 2108: Proof of amount in controversy

Search 28 U.S.C. § 2108 : US Code - Section 2108: Proof of amount in controversy

Where the power of any court of appeals to review a case depends
upon the amount or value in controversy, such amount or value, if
not otherwise satisfactorily disclosed upon the record, may be
shown and ascertained by the oath of a party to the case or by
other competent evidence.