Krisanapol Vichapan. 1992. Photogeology and gravity survey of the annular depression landform in parts of Changwat Surin and Roi-et. Graduate School, Chulalongkorn University;
Krisanapol Vichapan. (1992) Photogeology and gravity survey of the annular depression landform in parts of Changwat Surin and Roi-et . Chulalongkorn University/Bangkok.
Krisanapol Vichapan. Photogeology and gravity survey of the annular depression landform in parts of Changwat Surin and Roi-et. . Bangkok:Chulalongkorn University, 1992.
Krisanapol Vichapan. (1992) Photogeology and gravity survey of the annular depression landform in parts of Changwat Surin and Roi-et . Chulalongkorn University/Bangkok.