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3. Children’s behavioral understanding of knowledge formation in themselves and others;Esbensen;Cognitive Development,1997
4. Knowing how you know: Young children’s ability to identify and remember the sources of their beliefs;Gopnik;Child Development,1988
5. Kuczaj, S. (1976). -Ing, -s and -ed: A study of the acquisition of certain verb inflections. Unpublished doctoral dissertation, University of Minnesota.