The correct book reference is...

A) Shotton, M. A. (1989). Computer addiction? A study of computer dependency. Taylor & Francis.
B) Shotton, M. A. (1989). Computer addiction? A study of computer dependency. Taylor & Francis.
C) Shotton, M. A. (1989) Computer addiction? A study of computer dependency. Taylor & Francis.
D) Shotton, M. A. (1989). Computer Addiction? A Study of Computer Dependency. Taylor & Francis.