Benjamas Khamsakul. 1998. The attitude of So (Thavung) ethnic group toward their own language and its use : case study of Nong Waeng village, Pathumwapi subdistricts, Song Dao district, Sakon Nakhorn province. , Mahidol University;
Benjamas Khamsakul. (1998) The attitude of So (Thavung) ethnic group toward their own language and its use : case study of Nong Waeng village, Pathumwapi subdistricts, Song Dao district, Sakon Nakhorn province . Mahidol University/Bangkok.
Benjamas Khamsakul. The attitude of So (Thavung) ethnic group toward their own language and its use : case study of Nong Waeng village, Pathumwapi subdistricts, Song Dao district, Sakon Nakhorn province. . Bangkok:Mahidol University, 1998.
Benjamas Khamsakul. (1998) The attitude of So (Thavung) ethnic group toward their own language and its use : case study of Nong Waeng village, Pathumwapi subdistricts, Song Dao district, Sakon Nakhorn province . Mahidol University/Bangkok.