Leelavathi H P, Dr. J Prakash. “Two Stage Fusion Scheme Based on a Curvelet With Gradient Technique for Integration of SAR Image on PAN Image to Improve the Spatial Resolution.”. International Journal of Advanced Science and Technology, Vol. 29, no. 05, May 2020, pp. 4041 -53, http://sersc.org/journals/index.php/IJAST/article/view/13670.