Fracture Toughness Proceedings of the 1971 National Symposium on Fracture Mechanics Part 2 : Proceedings of the 1971 National Symposium on Fracture Mechanics University of Illinois Urbana-Champaign, Ill., 31 Aug.-2 Sept. 1971 : ASTM STP No.514 STP 514 - H. T. Corten, J. P. Gallagher (American Society for Testing and Materials (ASTM), 1972)