Section 2701 - Contracts concerning succession(a) Establishment of contract.--A contract to die intestate or to make or not to revoke a will or testamentary provision or an obligation dischargeable only at or after death can be established in support of a claim against the estate of a decedent only by:(1) provisions of a will of the decedent stating material provisions of the contract;(2) an express reference in a will of the decedent to a contract and extrinsic evidence proving the terms of the contract; or(3) a writing signed by the decedent evidencing the contract.(b) Joint will or mutual wills.--The execution of a joint will or mutual wills does not create a presumption of a contract not to revoke the will or wills.1992, Dec. 16, P.L. 1163, No. 152, § 6, imd. effective.