Donruetai Kovathanakul และ Pibul Jinawath. (2008) Sustainable Tourism Development Plan for the City of Nan. Silpakorn University:ม.ป.ท.Donruetai Kovathanakul และ Pibul Jinawath. 2008. Sustainable Tourism Development Plan for the City of Nan. ม.ป.ท.:Silpakorn University;Donruetai Kovathanakul และ Pibul Jinawath. Sustainable Tourism Development Plan for the City of Nan. ม.ป.ท.:Silpakorn University, 2008. Print.