1. “Tentative Method of Test for Plane Strain Fracture Toughness of Metallic Materials (ASTM Designation: E399-72T),” 1972 Annual Book of Standards, Part 31, ASTM, Phila. (1972).
2. Srawley, J. E. and Brown, Jr., W. F., “Fracture Toughness Test Methods, Fracture Toughness Testing and its Applications,” ASTM STP 381, ASTM, 133 (1965).
3. McClintock, F. A. and Walsh, J. B., “Friction on Griffith Cracks in Rocks under Pressure,” Proc. Fourth U.S. Nat. Congr. App. Mech., 1015–1021 (1962).
4. Hardy, M. P., “Fracture Mechanics Applied to Rock,” Ph.D. thesis, University of Minnesota (Dec. 1973).
5. Griffith, A. A., “The Theory of Rupture,” Proc. of First Int'l. Cong. on Appl. Mech., 55 (1924).