31 authorities of the Republic of Panama may require the registration of the appropriate documents to establish juridical presence in the Republic of Panama. (e) The contractor shall not be obliged to pay any tax or other assessment" to the Republic of Panama on income derived under a contract with the Commission, so long as he is taxed in the United States at a rate substantially equivalent to the corresponding taxes and assessments of the Republic of Panama. (f) The contractor may move freely within the Republic of Panama, and shall have exemptions from customs duties and other charges, as provided for United States citizen employees in Articles XIV and XVI of this Agreement. (g) The contractor may use public services and installations in accordance with the terms and conditions of Article XIII of this Agreement and, on a non-discriminatory basis, shall pay the Republic of -Panama highway tolls and taxes on plates for private vehicles. (h) The contractor shall be exempt from any taxes imposed on depreciable assets belonging to him, other than real estate, which are used exclusively for the execution of contracts with the United States. (i) The contractor may use the services and facilities provided for in Articles X and XVIII of the Agreement in Implementation of Article IV of the Panama Canal Treaty, ['I signed this date, to the extent such use is authorized by the United States; provided, however, that after five years from the entry into force of this Agreement, the use of military postal services by such contractors 'TIAS 10032; 33 UST. TIAS 10031 83-422 0 82 3