Shah, S. K. .; Ullah, K. .; Khan, A. .; Kkan, A. .; Khan, A. W. .; Qasim, I. . Single Versus Multi-Step Non-Rigid Medical Image Registration of 3D Medical Images: Single Versus Multi-Step Non-Rigid Medical Image Registration of 3D Medical Images. PPASA 2021, 53, 99–105.