Edelstein, W.S. & Valentin, R.A. Bounds and limit theorems for secondary creep in symmetric pressure vessels, report, August 1, 1974; (https://digital.library.unt.edu/ark:/67531/metadc1023364/m1/1/: accessed May 25, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .