(1) Any writing in existence when a will is executed may be incorporated by reference if the language of the will manifests this intent and describes the writing sufficiently to permit its identification.
(2) Whether or not the provisions relating to holographic wills apply, a will may refer to a written statement or list to dispose of items of tangible personal property not otherwise specifically disposed of by the will, other than money, evidences of indebtedness, documents of title, securities, and property used in trade or business.
(3) To be admissible under this subsection as evidence of the intended disposition, the writing must either be in the handwriting of the testator or be signed by him or her and must describe the items and devisees with reasonable certainty.
(4) The writing may be: Referred to as one to be in existence at the time of the testator's death;
(5) Prepared before or after the execution of the will;
(6) Altered by the testator after its preparation; and
(7) A writing which has no significance apart from its effect upon the dispositions made by the will.