8Martynyuk P A. Features of hydraulic fracture growth in the com- pression field. J Min Sci, 2008,44(6) :544.
9Jeffrey R G, Enever J R, Ferguson T, et al. Small-scale hydrau- lic fracturing and mineback experiments in coal seams // Pro- ceedings of the 1993 International Coalbed Methane Symposium. Birmingham, 1993 : 79.