Kritsana Canilao และ Somsonge Burusphat. (2010) Tonal geography of the provinces of central Thailand. Mahidol University:ม.ป.ท.Kritsana Canilao และ Somsonge Burusphat. 2010. Tonal geography of the provinces of central Thailand. ม.ป.ท.:Mahidol University;Kritsana Canilao และ Somsonge Burusphat. Tonal geography of the provinces of central Thailand. ม.ป.ท.:Mahidol University, 2010. Print.