More information regarding telecommunication standards, specifications and recommendations are available from the following links:

Telecommunication Standards, Specifications and Recommendations
3GPP Specifications
3GPP2 Specifications
ANSI - American National Standards Institute
ACIF - Australian Communications Industry Forum
ART - Autorité de Régulation des Télécommunications
Australian Standards
BELL Interface Specifications
BT - British Telecom - SINet
BSI - British Standards Online
CEPT - European Conference of Postal and Telecommunications Administrations
CRTC - Canadian Radi-television and Telecommunications Commision
Ecma International
ETSI - European Telecommunications Standards Institute
Eurescom - European Institute for Research and Strategic Studies in Telecommunications
FCC - Federal Communications Commission
IETF - The Internet Engineering Task Force
ITU - International Telecommunication Union
NICC - Network Interoperability Consultative Commitee
Nortel Interface Specifications
OFTA - Office of the Telecommunications Authority (Hong Kong)
Open Mobile Alliance (WAP Forum)
SCC - Standards Council of Canada
TeleManagement Forum
TIA - Telecommunications Industry Association
Telcordia Technologies (Bellcore)
TTC - The Telecommunication Technology Committee
United States Patent and Trademark Office
Numbering Plans
International Numbering Plans
National Numbering Plans
Country Calling Codes
ASN.1 Object Identifier (OID) Repository
Object Identifier (OID) Repository