APA (7th ed.) Citation

Oftel. (1991). Numbering for telephony services into the 21st century : a report to Oftel / by Ovum Limited: A report to Oftel. H.M.S.0..

Chicago Style (17th ed.) Citation

Oftel. Numbering for Telephony Services into the 21st Century : A Report to Oftel / by Ovum Limited: A Report to Oftel. London: H.M.S.0., 1991.

MLA (9th ed.) Citation

Oftel. Numbering for Telephony Services into the 21st Century : A Report to Oftel / by Ovum Limited: A Report to Oftel. H.M.S.0., 1991.

Warning: These citations may not always be 100% accurate.