Art. 9. The civilians interned in Switzerland at the moment when this agreement goes into effect will be freed from internment. Art. 12. Civilians who return to their country under the present agreement cannot be employed in military service, either at the front, or in the war zone, or in the interior of occupied enemy territory, or in the territories or possessions of an allied State. Art. 13. The arrangements for the liberation of civilians shall be put into operation immediately after this agreement goes into effect. Reckoning from that date, the transportation ought to be finished in a space of not more than three months for civilians now actually interned and six months for those interned at some time in the past. This transportation will be furnished free. The following articles deal with the population of occupied territory: Art. 17. The inhabitants of occupied territory cannot be compelled to work, except under the following rules: The work must be done under the best material and moral conditions, with due regard to personal aptitudes, social conditions, sex, age, and the physical status of the workers. Members of a family, so far as possible, must not be separated. Their labors must never involve any obligation to take part in war operations against their own country. Work can be demanded only (a) as service for the needs of the army of occupation, within the limitations laid down in Article 52 of The Hague Convention regarding war on land; (b) with the object of preventing idleness on the part of persons capable of working, who are supported at public expense, and who have refused voluntary employment; (c) with the object of providing, in the absence of other means, for the existence of the population. Art. 18. Persons compelled to work under Article 17 must be employed, with the exception mentioned, in the locality of their domicile or in its immediate neighborhood. If for military or economic reasons an inhabitant has to be removed from his home in order to put him at work, this removal shall not in any case take him outside the occupied territory, nor shall it bring persons whose residence is more than thirty kilometers from the firing line within the limits of that zone. Suitable provision shall be made for housing and food for workers who shall receive fair remuneration, and, if need be, medical service. Besides rest periods and normal changes they shall be given permission as often as possible to visit their families, with whom they shall also be allowed to correspond and exchange parcels.