FRACTURE MECHANICS EVALUATION OF REACTOR VESSEL STEELS. Quarterly Progress Report for the Period Ending December 31, 1967., report, January 1, 1968; (https://digital.library.unt.edu/ark:/67531/metadc1034193/m1/1/: accessed April 20, 2019), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .