PTA must be notified of a merger, as referred to in the first paragraph, no later than one week after an agreement thereto is concluded or public notification given of a take-over offer or that a specific party has gained control of an undertaking. PTA shall notify the undertaking concerned within 30 days of receiving satisfactory notification if it sees cause to examine the case. A decision on cancellation or change of rights shall be taken no later than three months after notification by PTA. Should an undertaking fail to fulfil its obligation to give notification as provided for in the first paragraph, PTA may examine the case and take a decision when the Admini-stration learns of the merger in question. Procedure shall be as provided for in this paragraph. If an undertaking holding the rights to use frequencies is divided into two or more undertakings, PTA may authorise the transfer of rights to use frequencies, or a portion of those rights, to an undertaking created through such division. Such authorisation shall be subject to the condition that it will neither interfere with competition nor effective use of the frequency spectrum and that the new undertaking is regarded as capable of fulfilling the conditions inherent in these rights. The provisions of the first to third paragraphs shall also apply as appropriate to rights to use numbers. Article 9 Limits in assignment of rights PTA may limit the number of assignments of rights to use specific frequencies if such is necessary to ensure efficient use of frequencies. Emphasis shall be placed on users' interests and stimulating competition. All interested parties, including users, shall be given the opportunity to express their views on limits to the rights before PTA takes its decision, which shall be published together with its grounds. The method used to assign rights shall be published and applications invited by advertise-ment. PTA shall regularly review the limits which have been set, for instance, at the request of electronic communications undertakings concerned. If further rights to use frequencies can be assigned, an advertisement shall invite applications. Article 10 Conditions for use of frequencies and numbers PTA may attach the following conditions to rights to use frequencies: a. that assignment of frequencies shall apply only to certain services or types of networks or technology, including as applicable, the assignment of exclusive rights for transmission of special content or for specific audiovisual services; b. that use of frequencies is efficient; c. that the equipment and operations of an electronic communications undertaking minimise harmful interference and the exposure of the general public to electromagnetic radiation; d. that the period of validity for the service in question shall be limited and subject to any changes in the national frequency plan; 7/34