*{{cite journal|last1=Bates|first1=M|year=1995|title=Models of natural language understanding|journal=Proceedings of the National Academy of Sciences of the United States of America|volume=92|issue=22|pages=9977–9982|doi=10.1073/pnas.92.22.9977|pmid=7479812|pmc=40721|bibcode=1995PNAS...92.9977B}} | *{{cite journal|last1=Bates|first1=M|year=1995|title=Models of natural language understanding|journal=Proceedings of the National Academy of Sciences of the United States of America|volume=92|issue=22|pages=9977–9982|doi=10.1073/pnas.92.22.9977|pmid=7479812|pmc=40721|bibcode=1995PNAS...92.9977B}} |