Directive 97/33/EC of the European Parliament and of the Council of 30 June 1997 on interconnection in telecommunications with regard to ensuring universal service and interoperability through application of the principles of open network provision (ONP), (OJ L 199, 26.7.97, p. 32), as amended by Directive 98/61/EC of the European Parliament and of the Council of 24 September 1998 with regard to operator number portability and carrier pre-selection (OJ L 268, 3.10.1998, p. 37).
Direktiva 97/33/ES Evropskega parlamenta in Sveta z dne 30. junija 1997 o medomrežnem povezovanju v telekomunikacijah zaradi zagotavljanja univerzalne storitve in medobratovalnosti ob uporabi načel zagotavljanja odprtosti omrežij (ONP), (UL L 199, 26.7.97, str. 32), kakor je bila spremenjena z Direktivo 98/61/ES Evropskega parlamenta in Sveta z dne 24. septembra 1998 v zvezi s prenosljivostjo številk operaterja in predizbiro operaterja (UL L 268, 3.10.1998, str. 37).