Aswin Sangpikul. 2010. Good practices for ecotourism tour operators for the sustainable tourism development of Thailand. Bangkok:Dhurakij Pundit University;
Aswin Sangpikul. (2010) Good practices for ecotourism tour operators for the sustainable tourism development of Thailand. Dhurakij Pundit University:Bangkok.
Aswin Sangpikul. Good practices for ecotourism tour operators for the sustainable tourism development of Thailand. Bangkok:Dhurakij Pundit University, 2010. Print.
Aswin Sangpikul. (2010) Good practices for ecotourism tour operators for the sustainable tourism development of Thailand. Dhurakij Pundit University:Bangkok.