Hai, Nguyen, 		Quy Hoi, Nguyen, AND 		Mai Hoa, Tran.
" Territorial organization for ecotourism development in Hoang Lien National Park, Sapa District, Lao Cai Province" <em>VNU Journal of Science: Earth and Environmental Sciences</em> [Online], Volume 24 Number 1 (15 March 2008)