Treaties, States Parties and Commentaries
Treaties and Documents
Geneva Conventions of 1949 and Additional Protocols, and their Commentaries
Historical Treaties and Documents
Instructions for the Government of Armies of the United States in the Field (Lieber Code). 24 April 1863.
Section VIII : Armistice -- Capitulation - Art. 135.
Art. 135. An armistice is the cessation of active hostilities for a period agreed between belligerents. It must be agreed upon in writing, and duly ratified by the highest authorities of the contending parties.