Related Rule
Practice Relating to Rule 128. Release and Return of Persons Deprived of Their Liberty
Section G. Role of neutral intermediaries in the return process
Argentina’s Law of War Manual (1969) provides:
The Detaining Power, the Power on which the prisoners of war depend, and a neutral Power agreed upon by these two Powers, shall endeavour to conclude agreements which will enable prisoners of war to be interned in the territory of the said neutral Power agreed until the close of the hostilities. 
Argentina, Leyes de Guerra, RC-46-1, Público, II Edición 1969, Ejército Argentino, Edición original aprobado por el Comandante en Jefe del Ejército, 9 May 1967, § 2.097.