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.
Atenció: Aquestes cites poden no estar 100% correctes.