61 STAT.] MULTILATERAL-POSTAL UNION-SEPT. 25, 1946 Americas and Spain, or among the students of the same through their directors will enjoy a 50% reduction in the ordinary rate so long as their weight does not exceed 1 kilogram and they satisfy the other conditions for their postal classification. ARTICLE 15 Special services The High Contracting Parties may, on the basis of special agree- ments or by correspondence, extend to the other countries of the Postal Union of the Americas and Spain such postal services as they carry on or may in the future establish within their respective countries. ARTICLE 16 Service forms sent by air mail 1. The forms provided for in the Regulations of Execution of the Universal Postal Convention for requests for the withdrawal of cor- respondence or change of address, as well as those provided for in- quiries regarding articles of correspondence and requests for informa- tion, may be dispatched by air mail. 2. To this end the Forms C-11, C-12 and C-13 will be differentiated in the following manner: blue color for those which must be forwarded by air mail and pink for those which must be also answered by air mail. 3. The forwarding by air will give rise to the collection of a sup- plementary fee which the sender will pay when he fills out his form. It will be the equivalent to the postage for an air mail letter of 5 grams to the country of destination or to double this rate if a prepaid reply by air is requested. These payments will accrue exclusively to the country which collects them. ARTICLE 17 Official language Spanish is adopted as the official language for matters relative to the postal service. Nevertheless, countries whose language is not this may use their own. ARTICLE 18 Protection and exchange of postal functionaries 1. The Administrations of the contracting countries will be obliged to lend mutually, upon request, the cooperation required by their employees charged with the transportation of correspondence in transit through such countries. Likewise, they will furnish all manner of facilities to such functionaries as one Administration may agree to send to any other to carry on studies regarding the development and perfection of postal services. 2. The Administrations through the intermediary of the Inter- national Office of Montevideo, will come to agreements to effect an exchange of functionaries. Notwithstanding what has been established previously, the Ad- ministrations may also make agreements to send functionaries for 3511 54 Stat. 2105 . 54 Stat. 2141, 2142, 2143. Supplementary fee. Cooperation of oon- tracting countries. Agreements respect- ing functionaries.
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