Teaney, P. E. & Selle, J. E. An Evaluation of the Use of a Quantitative Image Analyzer to Determine Microhardness Values, article, October 1, 1971; (https://digital.library.unt.edu/ark:/67531/metadc926104/m1/1/: accessed November 12, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .