[9] Evidence which merely establishes facts from which the falsity of an alleged perjured statement may or may not be inferred does not meet the requirement of the direct evidence rule applicable to perjury cases. ( People v. Maxwell, supra, 118 Cal. 50, 54; People v. O'Donnell, supra, 132 Cal.App.2d 840, 846-849; People v. Burcham, supra, 69 Cal.App. 614, 616-619; People v. Burcham, 62 Cal.App. 649, 656 [ 217 P. 558].) [8b] In the case at bar the testimony just related was supplemented by that of three handwriting experts who testified that, in their opinion, the defendant wrote the questioned endorsement "Rita Burney"; based their opinions upon a comparison of this endorsement with the handwriting exemplars of the defendant which were admitted in evidence; and detailed their reasons therefor, pointing out areas of similarity between the endorsement signature and the handwriting exemplars.