Jones, D.P.; Gordon, J.L.; Hutula, D.N.; Banas, D. & Newman, J.B. An elastic-perfectly plastic flow model for finite element analysis of perforated materials, article, February 1, 1999; (https://digital.library.unt.edu/ark:/67531/metadc704651/m1/1/: accessed April 24, 2019), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .