Text and voice : complements, substitutes or both? /
Andersson, Kjetil.
Foros, Øystein.
Steen, Frode.
Centre for Economic Policy Research (Great Britain)
London : Centre for Economic Policy Research,
2006.
Caption title.
Includes bibliographical references (p. 16-17).
Cell phone services industry.
Cell phone systems.
Text messages (Telephone systems).
Also available from the CEPR World Wide Web site (www.cepr.org).