1. An Analysis of Urban Land Development Using Multi-Criteria Decision Model and Geographical Information System (A Case Study of Babolsar City);Lotfi;American Journal of Environmental Sciences,2009
2. N. W. Chan, I.K. Chan, and K. Kumar, 2003. “Ecotourism in the Penang National Park: Issuses and challenges”, in Ecotourism:Issues and challenges, N.W. Chan, Ed., ed Penang: School of Humanties, Universiti Sains Malaysia.
3. Building a geographic info-structure for sustainable development planning on a small island developing state;Perkins;Landscape and Urban Planning,2006
4. Penang, “Safety guidelines for hillsite Development, 2012. http://www.mppp.gov.my/documents/10124/20fa2155-5a83-4644-8629-64da6405f4e1, Reterieved on 11-11-2012,”.
5. The Potentials, Threats and Challenges in Sustainable Development of Penang National Park;Wern;Malaysian Journal of Environmental Management,2010