1. Notes on the Synthesis of Form;Alexander,1964
2. Alliance for Telecommunications Industry Solutions (ATIS), 2000. ANS T1.523-2001, telecom glossary 2000. www.atis.org/tg2k/ (accessed December 19th, 2004).
3. Industrial Organization;Bain,1968
4. Bensinger, A., 2004. Standard & Poor's Industry Surveys: Communications Equipment.