We approve the opinion of the Court of Civil Appeals in the holding that the *300grounds of error alleged in the application for writ of certiorari were sufficient to invoke the jurisdiction of the district court. 498 S.W.2d 680. See Rules 344 et seq., Texas Rules of Civil Procedure.

The further writings of the court upon the question of estoppel were not brought forward and are not before us; therefore the application for writ of error is refused, no reversible error. See Shambry v. Housing Authority of City of Dallas, 152 Tex. 122, 255 S.W.2d 184 (1953); Wilson, Precedent Evaluation, 24 Tex.B.J. 1037.