Where bonds, when issued by a city, contain recitals insuring that "all preliminary steps had been taken in manner and form required by law", if it appears later when bonds are in the hands of a purchaser that a fact stated in the recitals is untrue, the city is estopped to so prove or contend. South Sioux City v. Hanchett Bond Co., 19 F.2d 476 (8th Cir. 1927).

Findings of a board, authorized by the Legislature to determine questions of fact upon which limitations of amount of issue of bonds depends, are conclusive in favor of bona fide purchasers of such bonds. Chilton v. Town of Gratton, 82 F. 873 (Cir. Ct., D. Neb. 1897).