Foreign territories or parts of territories may be incorporated in the customs area by international treaties or agreements.
Portions of territory may be excluded from the customs area in accordance with special requirements. In the case of free ports this exclusion may be discontinued only by an amendment to the Constitution.
Districts excluded from the customs area may be included within a foreign customs area by international treaties or agreements.
All products of nature or industry, as well as works of art, which are subjects of free commerce within the Commonwealth, may be transported in any direction across State and municipal boundaries. Exceptions are permissible by authority of national law.
ARTICLE 83
Customs duties and taxes on articles of consumption are administered by the national authorities.
In connection with national tax administration by the national authorities, arrangements shall be provided which will enable the States to protect their special agricultural, commercial, trade and industrial interests.
ARTICLE 84
The Commonwealth has authority to regulate by law: