Gaya APA

Trooboff, S, K. et al (1995). Travel sales and customer service : the institute of certified travel agents . Burr Ridge, IL: Irwin Mirror Press.

Gaya MLA

Trooboff, Stevan, K.. et al. "Travel sales and customer service : the institute of certified travel agents". Burr Ridge, IL: Irwin Mirror Press, 1995. Text.