449 A.2d 784 William T. Zander, Petitioner v. Workmen’s Compensation Appeal Board (Warrington Equipment Company), Respondents. Commonwealth Court of Pennsylvania.Argued June 7, 1982 August 24, 1982. Workmen’s compensation — Second work-related injury — Burden of proof — Credibility — Causation — Medical testimony. 1. A workmen’s compensation claimant, asserting that a prior disability has been […]