77 Pa. Stat. § 1401 : Statutes (Unconsolidated) — WORKERS' COMPENSATION — OCCUPATIONAL DISEASES — ELECTIVE COMPENSATION — Agreement for acceptance; negligence; disability caused by violation of law; burden of proof; maximum compensation; minors; disease peculiar to occupation or industry; compensation for disability due to silicosis, anthraco-silicosis, coal worker's pneumoconiosis, or asbestosis; presumption; which employer liable; notice, payments in instalments