In Permian Oil Co. v. Smith, 129 Tex. 446, 107 S.W.2d 564 (1937), the Supreme Court of Texas discussed both res judicata and collateral estoppel. Permian Oil held that for res judicata purposes, only the judgment should be inquired into, absent ambiguity in the judgment. See Permian Oil, 107 S.W.2d at 567. Where the judgment is ambiguous, extrinsic evidence is admissible to help interpret the judgment. See id. If the issue is one of collateral estoppel, the Court held that the whole record of the first case is admissible in order to determine whether the issue involved had already been resolved in the prior suit. See id. At no time did the Permian Oil court mandate the necessity of introducing both the pleadings and the judgment from the prior suit. The Court did state that one must look only to the pleadings and the judgment, absent ambiguity, in cases where the original judgment is being collaterally attacked; but this has no bearing on the case at bar or on the Traweek line of cases. See Permian Oil, 107 S.W.2d at 568.