Theories Contrasted: Rudy's Variability in the Associative Process (V.A.P.) and Martin's Encoding Variability, thesis, December 1976; (https://digital.library.unt.edu/ark:/67531/metadc503837/m1/29/: accessed July 18, 2024), University of North Texas Libraries, UNT Digital Library, digital.library.unt.edu; .