R. S. Morgan, M. Abd El-Hady, I. S. Rahim, J. Silva, and S. Ribeiro. “EVALUATION OF VARIOUS INTERPOLATION TECHNIQUES FOR ESTIMATION OF SELECTED SOIL PROPERTIES”. GEOMATE Journal, vol. 13, no. 38, Mar. 2017, pp. 23-30, https://geomatejournal.com/geomate/article/view/1433.