Uthaisri, P., P. Oopkao, N. Sukpasong, and M. Chaichompu. “Comparison of Elevation in a straight line from Leveling with Level and Global Navigation Satellite Systems”. RMUTL Engineering Journal, vol. 10, no. 2, Dec. 2025, pp. 1-9, doi:10.14456/rmutlengj.2025.9.