References & Bibliography

1. International Telecommunication Union - Standardization Sector (ITU-T) Home Page - International organization that develops standards to facilitate the interconnection of telecommunication systems on a worldwide scale.  ADSL2 has been proposed exclusively by the ITU (as to date).  ADSL standard has also been proposed by the American National Standards Institute (ANSI) and is known as T1.413.
2. DSLForum  and DSLlife -  DSL Forum is a non profitable organization, committed to serving the global customer by anticipating needs, and developing DSL solutions to improve lives. DSLlife is a subchannel site of dslforum serves as a consumer's guide to xDSL technology.
3. ITU Document BM-027R1: G.hs: Implementation and Newbie Information
4. TR-017 DSL forum's technical report based on ATM over ADSL recommandation
5. xDSL techniologies and ADSL by petri hakula, harry mantayla, and nicklas beijar. Special thanks to Vesa Kosonen fron helsinki university of technology for letting us use the article.
6. A technical  article about modulation techniques from Nextep Broadband - a communication company offering solutions in high speed comunication networking. 
7.  An article about VDSL based on ITU standardization from analog devices - a manufacturer specializes in signal processing solutions.
8. Aware - worldwide leader in the development and marketing of intellectual property for broadband communications.  Its site contains whitepapers for ADSL2 and its developments.
9. Whatis , Webopedia , and ATIS - for misc technical defintions
10. John A. C. Bingham - "ADSL , VDSL, and Multicarrier Modulation", published by john willy & sons
11. Commdesign - an EE Times community, serves as online technical resource center for technical study for development of communication systems.  It had some very interesting articles regarding current development in ADSL2 and VDSL2.
12. Ikanos communications - a leading communications chip manufacturer in the field of high speed broadband, offers whitepapers about vdsl2.
13. Sunrise Telcom - Sunrise Telecom is a global leader in providing service verification equipment for a growing variety of communications environments and technologies.  Note their article: "PING Testing over xDSL End-to-End Service Verification" where they explain the various encapsaulation schemes over adsl.
14. PC magazine and HW-server -  sites offering technical network resources.
15. the G.I.I.F  (no longer active) for isdn over ADSL information.
16. Acterna - communications test and management solutions 
17. Cisco systems - offerring technical tutorials about ADSL technologies.  especially noted is the article about "Delivering Multicast Video Over Asymmetric Digital Subscriber Line".