ICRC databases on international humanitarian law
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 III : Deserters -- Prisoners of war -- Hostages -- Booty on the battle-field. - Art. 61.
Art. 61. Troops that give no quarter have no right to kill enemies already disabled on the ground, or prisoners captured by other troops.