Соответствующая норма
Burundi
Practice Relating to Rule 125. Correspondence of Persons Deprived of Their Liberty
Burundi’s Regulations on International Humanitarian Law (2007) states: “Prisoners of war must be allowed to … send and receive letters and cards … [as well as] to receive individual packages or collective remittances.” 
Burundi, Règlement n° 98 sur le droit international humanitaire, Ministère de la Défense Nationale et des Anciens Combattants, Projet “Moralisation” (BDI/B-05), August 2007, Part I bis, p. 56.
The Regulations also states that prisoners of war “have the right to send and receive their correspondence in return for censorship”. 
Burundi, Règlement n° 98 sur le droit international humanitaire, Ministère de la Défense Nationale et des Anciens Combattants, Projet “Moralisation” (BDI/B-05), August 2007, Part I bis, p. 105.