TY  - BOOK
AU  - Varian Hal R, and others
TI  - Economics of Information technology:  An introducti   
T2  - Raffaele Mattioli Lecture Series
SN  - 0521605210
U1  - X:(D6,9(B), P4 
PY  - 2004///
CY  - Cambridge
PB  - Cambridge University Press        
N1  - Bibliography: p 87-96
ER  -