6DEERE D U. Rock quality designation (RQD) after 20 years[R]. Vicksburg, MS: Waterways Experimental Station, 1989.
7DEERE D U, DEERE D W. The rock quality designation(RQD) index in practice[C]//Rock Classification Systems for Engineering Purposes. U.S: American Society for Testing and Materials Special Technical Publication 1988, 984: 91-101.
8SEN Ze-kai. RQD models and fracture spacing[J]. Journal of Geotechnical Engineering, 1984, 10(2): 203 -216.
9SEN Z, KAZI A. Discontinuity spacing and RQD estimates from finite length scanlines[J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1984, 21(4): 203-212.
10PRENSKY S E. Advances in borehole imaging technology and application[C]//Borehole Imaging: Applications and Case Histories. London: Geological Society, 1999:1-43.