Cita APA (7th ed.)

BARKER,ALAN. (2010). IMPROVE YOUR COMMUNICATION SKILL. KOGAN PAGE LTD.

Cita Chicago (17th ed.)

BARKER,ALAN. IMPROVE YOUR COMMUNICATION SKILL. NEW-YORK: KOGAN PAGE LTD, 2010.

Cita MLA (9th ed.)

BARKER,ALAN. IMPROVE YOUR COMMUNICATION SKILL. KOGAN PAGE LTD, 2010.