5Enadd S. Ebbini, Charles A. Cain, IEEE Trans. Ultrason. Ferroelec[J]. Freq. Contr., 1989,36(6) :541 - 547.
6R. W. Gerchberg, W. O. Saxton. Phase determination from image and diffraction plane pictures in the electron microscope[J]. Optik, 1971, 34(3) :275 - 284.