Nielsen, Rodney D.; Ward, Wayne; Martin, James H. & Palmer, Martha. Extracting a Representation from Text for Semantic Analysis, paper, June 2008; (https://digital.library.unt.edu/ark:/67531/metadc1042597/m1/1/: accessed March 23, 2019), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .