(a) By an expressed intention of the testator or settlor contained in a will or in an instrument in writing whereby a trust estate is created inter vivos, any or all of the powers or any portion thereof enumerated in this article, as they exist at the time of the signing of the will by the testator or at the time of the signing by the first settlor who signs the trust instrument, may be, by appropriate reference made thereto, incorporated in the will or other written instrument with the same effect as though such language were set forth verbatim in the instrument.

(b) Incorporation of one or more of the powers contained in this article, by reference to the appropriate portion of Code Section 53-12-232, shall be in addition to and not in limitation of the common-law or statutory powers of the fiduciary.

(c)(1) A provision in any will or trust instrument which incorporates powers by citation to Georgia Laws 1973, page 846; Code 1933, Section 108-1204 (Harrison); or Code Section 53-15-3 and which was valid under the law in existence at the time the will was signed by the testator or at the time of the signing by the first settlor who signs the trust instrument shall be effective notwithstanding the subsequent repeal of such statute.

(2) A provision in any will or trust instrument which was signed by the testator or by the first settlor to sign after June 30, 1991, but before July 1, 1992, and which incorporates powers by citation to Code Section 53-15-3 shall be deemed to mean and refer to the corresponding powers contained in Code Section 53-12-232.