9[4]K J Ellefsen, C H Cheng, K H Tubman. Estimating Phase velocity and attenuation of guided waves in acoustic logging data. Geophysics, 1988, 54(8): 1054~1059.
10[5]J Zemanek, D M Williams, et al. Shear-Wave Logging Using Multipole Sources. The Log Analyst,1991: 233~241.