Darnbrough, J.: 'Market aspects of UMTS', IET Conference Proceedings, 1998, p. 4-4, DOI: 10.1049/ic:19980111
IET Digital Library, https://digital-library.theiet.org/;jsessionid=fn8okl8disgm9.x-iet-live-01content/conferences/10.1049/ic_19980111