We affirm the judgment here appealed from on the basis of the opinions and orders of the District Court dated August 5, 1977 and November 13,1979. App. 819 and 1314. In our view, the District Court opinions properly held that the law governing this case is the law of the District of Columbia, D.C.Code Ann. §§ 15-108, 15-109 (1973); that the disputed contract included an implied condition requiring WMATA to make equitable adjustments of claims under the contract within a reasonable period of time; that a failure to comply with that condition could give rise to a claim for interest under the parties’ contract; that there was no substantial evidence to support WMATA’s finding of no unreasonable delay; and that, therefore, interest was properly given under the contract pursuant to applicable District of Columbia law.

So ordered.