Werner, Jill C.; Robinett, Rush D. & Petterson, Ben J. Swing-Free Movement of Simply Suspended Objects Employing Parameter Estimation, report, June 1, 1990; (https://digital.library.unt.edu/ark:/67531/metadc1193169/m1/3/: accessed April 23, 2019), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .