A will may refer to a written statement, letter, or list to dispose of items of tangible personal property not otherwise specifically disposed of by the will, except tangible personal property used in trade or business. Tangible personal property, for purposes of this section, includes household goods, furnishings, furniture, personal effects, clothing, jewelry, books, works of art, ornaments, and automobiles. If the writing is dated and is either in the handwriting of the testator or is signed by testator, and if it describes the items and distributees with reasonable certainty, the personal representative shall distribute the described items of tangible personal property to the distributees entitled to them. The writing may be referred to as one to be in existence at the time of the testator’s death. The writing may be prepared before or after the execution of the will. The writing may be altered, added to, or changed in any respect by the testator after its preparation, and it may be a writing which has no significance apart from its effect upon the dispositions made by the will. Property passing by the writing shall be considered as property passing as a specific bequest under will.