Before revision: According to Brustoloni (1991) According tuo Maes (1995) Franklin and Graesser (1997) review different definitions and propose their definition They explain it Agent appearance Lee et al.
After revision: According to Brustoloni (1991) According to Maes (1995) Franklin and Graesser (1997) review different definitions and propose their definition They explain it Agent appearance Lee et al.