or engaged in actual warfare, or a mariner at sea, must execute his or her will according to the following provisions— (a) the testator shall sign or affix his or her mark to the will, or it shall be signed by some other person in his or her presence and by his or her direction; (b) the signature or mark of the testator or the signature of the person signing for him or her shall be so placed that it shall appear that it was intended thereby to give effect to the writing as a will; (c) the will shall be attested by two or more witnesses, each of whom must have seen the testator sign or affix his or her mark to the will, or have seen some other person sign the will in the presence and by the direction of the testator, or have received from the testator a personal acknowledgment of his or her signature or mark, or of the signature of that other person; and each of the witnesses must sign the will in the presence of the testator, but it shall not be necessary that more than one witness be present at the same time, and no particular form of attestation shall be necessary. 51. Incorporation of papers by reference. If a testator, in a will or codicil duly attested, refers to any other document then actually written, as expressing any part of his or her intentions, that document shall be considered as forming a part of the will or codicil in which it is referred to. PART IX—PRIVILEGED WILLS. 52. Privileged wills. Any member of the armed forces being employed in an expedition or engaged in actual warfare, or any mariner being at sea, may, if he or she has completed the age of eighteen years, dispose of his or her property by a will made as is provided in section 53 (hereafter referred to as a “privileged will”). 53. Mode of making privileged wills. (1) mouth. Privileged wills may be in writing or may be made by word of (2) The execution of a privileged will shall be governed by the