APA (7th ed.) Citation

Zeithaml, V. A., Parasuraman, A., & Berry, L. L. (1990). Delivering quality service: Balancing customer perceptions and expectations. The Free.

Chicago Style (17th ed.) Citation

Zeithaml, Valarie A., A. Parasuraman, and Leonard L. Berry. Delivering Quality Service: Balancing Customer Perceptions and Expectations. The Free, 1990.

MLA (8th ed.) Citation

Zeithaml, Valarie A., et al. Delivering Quality Service: Balancing Customer Perceptions and Expectations. The Free, 1990.