Patent Cooperation Treaty (PCT)
Article 31
(1) On the demand of the applicant, his international application shall be the subject of an international preliminary examination as provided in the following provisions and the Regulations.
(2)(a) Any applicant who is a resident or national, as defined in the Regulations, of a Contracting State bound by Chapter II, and whose international application has been filed with the receiving Office of or acting for such State, may make a demand for international preliminary examination.
(b) The Assembly may decide to allow persons entitled to file international applications to make a demand for international preliminary examination even if they are residents or nationals of a State not party to this Treaty or not bound by Chapter II.
(3) The demand for international preliminary examination shall be made separately from the international application. The demand shall contain the prescribed particulars and shall be in the prescribed language and form.
(4)(a) The demand shall indicate the Contracting State or States in which the applicant intends to use the results of the international preliminary examination ("elected States"). Additional Contracting States may be elected later. Election may relate only to Contracting States already designated under Article 4.
(b) Applicants referred to in paragraph (2)(a) may elect any Contracting State bound by Chapter II. Applicants referred to in paragraph (2)(b) may elect only such Contracting States bound by Chapter II as have declared that they are prepared to be elected by such applicants.
(5) The demand shall be subject to the payment of the prescribed fees within the prescribed time limit.
(6)(a) The demand shall be submitted to the competent International Preliminary Examining Authority referred to in Article 32.
(b) Any later election shall be submitted to the International Bureau.