28 U.S.C. § 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.

( June 25, 1948, ch. 646 , 62 Stat. 963 .)