1. Ahmad, S.A. (2009). Visitors ‘Willingness To Pay For An Entrance Fee: A Case Study Of Marine Parks In Malaysia. PhD Thesis.
2. Aminrad, Z., Zarina, S., & Hadi, A.S. (2010). Survey on Environmental Awareness among Environmental Specialists and Secondary School Science Teachers in Malaysia.
3. Perceptions of the environmental impacts of tourism: A comparative study of the attitudes of German, Russian and Turkish tourists in Kemer;Baysan;Antalya. Tourism Geographies,2001
4. Bash, J., & Bolton, S. (2001). Effects Of Turbidity And Suspended Solids on Salmonoids. Research Project.
5. Beharry-borg, N., & Scarpa, R. (2010). Economic valuation of coastal water quality improvements in Tobago, (January), 1-40.