Siu, R. C. S. (2019). Economic principles for the hospitality industry (First edition.). Routledge.
Παραπομπή σε μορφή Chicago (17η εκδ.)Siu, Ricardo Chi Sen. Economic Principles for the Hospitality Industry. First edition. Abingdon, Oxon: Routledge, 2019.
Παραπομπή σε μορφή MLA (9th εκδ.)Siu, Ricardo Chi Sen. Economic Principles for the Hospitality Industry. First edition. Routledge, 2019.