1. Ministry of Finance, The 2019 Budget Speech edition, Percetakan Nasional Malaysia Berhad. Access on 25 June 2023 (2019) https://www.mof.gov.my/portal/arkib/budget/2019/bs19.pdf.
2. Tourism Malaysia, Malaysia Tourism Statistics in Brief. Access on 25 June 2023 (2020) https://www.tourism.gov.my/statistics
3. Sabah Tourism, Sabah Tourism Board. Access on 25 Jun 2023 (2023) https://sabahtourism.net/statistics/
4. Ibrahim Y., Penerbit Dewan Bahasa dan Pustaka, Kuala Lumpur. Pp. 7-11 (2008)
5. Mapjabil J., Kanyo N. I., Penerbit Universiti Tun Hussein Onn Malaysia 93-94 (2014)