What is the test for determining the credibility of a document presented before the Court of Appeal?

An appellate court is one step removed from this process. We have no facilities for calling witnesses or determining the provenance of documents, and therefore no occasion or ability to evaluate the credibility of either. We thus may not disturb the factual findings of a trial court absent a clear showing that the court in some manner abused its discretion. (Smith v. Smith, supra, 1 Cal.App.3d at p. 958.) This necessarily means we may not presume the trial court abused its discretion; such abuse must be affirmatively established by the party challenging the trial court's actions. (Ibid.) Absent a clear abuse of discretion, we have no power to revise the lower court's judgment even if we would have made different findings and orders had the matter been submitted to us in the first instance, which it never is. (Ibid.)