474.155. A contract to make a will or devise, to revoke or not to revoke a will or devise, or to die intestate, if executed after January 1, 1981, can be established only by
(1) Provisions of a will stating material provisions of the contract;
(2) An express reference in a will to a contract and extrinsic evidence proving the terms of the contract; or
(3) A writing signed by the decedent evidencing the contract. The execution of a joint will or mutual wills does not create a presumption of a contract not to revoke the will or wills.
(L. 1980 S.B. 637)Effective 1-1-81