@ARTICLE{ey1,
  AUTHOR	    = {A. AAA and B. BBB and A. CCC and E. EEE},
  YEAR              = {1968}
}

@ARTICLE{ey2,
  AUTHOR	    = {A. AAA and B. BBB and A. CCC and D. DDD},
  YEAR              = {1968}
}

@ARTICLE{ey3,
  AUTHOR	    = {A. MMM and B. NNN},
  YEAR              = {1968}
}

@ARTICLE{ey4,
  AUTHOR	    = {A. MMM and B. NNN},
  YEAR              = {1968}
}

@ARTICLE{ey5,
  AUTHOR	    = {Aaa ZZZ and Bbb VVV},
  YEAR              = {1968}
}

@ARTICLE{ey6,
  AUTHOR	    = {Abb ZZZ and Bbb VVV},
  YEAR              = {1968}
}









