Qu, Y.; Verma, P.K.: 'Notion of cost and quality in telecommunication networks: an abstract approach', IEE Proceedings - Communications, 2005, 152, (2), p. 167-171, DOI: 10.1049/ip-com:20045058 IET Digital Library, https://digital-library.theiet.org/;jsessionid=1jhi8anyqwk23.x-iet-live-01content/journals/10.1049/ip-com_20045058