ICRC databases on international humanitarian law
Treaties and Documents
1949 Conventions and Additional Protocols, and their Commentaries
Historical Treaties and Documents
The Laws of War on Land. Oxford, 9 September 1880.
Part II : Application of general principles #III. Prisoners of war #A. Rules for captivity - Art. 66.
Art. 66. Prisoners may be interned in a town, a fortress, a camp, or other place, under obligation not to go beyond certain fixed limits; but they may only be placed in confinement as an indispensable measure of safety.