including other divisions of the undertaking, its subsidiaries or partners. Article 27 Obligations of electronic communications undertakings Where an electronic communications undertaking is deemed to have significant market power, PTA may impose on it obligations concerning transparency, non-discrimination, accounting separation, open access to specific network facilities, price control and cost accounting, as necessary for the purpose of strengthening effective competition. Article 28 Access to networks and services PTA may instruct electronic communications undertakings with significant market power to meet normal and reasonable requests for open access to public electronic communications networks, network elements, and associated facilities under certain conditions prescribed by the Administration, cf. however the third paragraph. Electronic communications undertakings may be required inter alia: a. to provide access to individual network elements or facilities, including unbundled access to local loops, b. to offer specified services on a wholesale basis for resale by third parties, c. to authorise open access to technical interfaces, protocols or other key technologies which are necessary to insure interoperability of services or virtual network services, d. to offer co-location or joint utilisation, including joint utilisation of cable ducts, buildings or masts, e. to offer services which insure interoperability of services to users, including intelligent network services or roaming on mobile networks, f. to offer access to operational support systems or similar software systems necessary to ensure competition in the provision of services, g. to interconnect networks or network facilities, h. to provide access for virtual networks, i. to provide access to other essential facilities. In determining whether to impose the obligations referred to in the first paragraph, PTA shall take into consideration whether it is: a. technically and financially realistic to use or install competing facilities in view of market developments and the nature and type of interconnection and access involved, b. feasible to provide the access proposed, c. justifiable, in view of the original investment by the owner of the facility and the risk taken in making the investment, d. to the advantage of competition in the longer term, e. inappropriate, in view of intellectual property rights, 15/34