There are several ways to claim foreign priority for a patent application. The first option is filing an international application under the Patent Cooperation Treaty (PCT). In order to utilize this option, at least one of the applicants has to be a national or a resident of a country that is a PCT Contracting State. Upon filing, the applicant picks a receiving office, which is a national patent office designated for receiving the PCT application. A competent receiving office belongs to a location in which one of the PCT applicants is entitled to file a PCT application. Each PCT member state has a competent receiving office for its residents and nationals. The International Bureau of the World Intellectual Property Organization (WIPO) also acts as a receiving office in which all applicants are entitled to file PCT applications. In that case, the applicant can file directly with WIPO. Thirty to 31 months after initial filing, the application then enters the national stage and the applicant can select the countries in which it would like to file.

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