Kossmann, M. (2006). Delivering Excellent Service Quality in Aviation: A Practical Guide for Internal and External Service Providers. Leuven, Belgium: Ashgate Publishing Limited. Retrieved from https://www.emeraldinsight.com/doi/abs/10.1108/09564230710778173, 04.05.2019.
Swire Group. (2019). The Swire Group: Our Story. Hong Kong, Hiina Rahvavabariik: The Swire Group. Retrieved from https://www.swire.com/en/global/home.php, 04.05.2019.