Vladimir G. Deineko Bettina Klinz Gerhard J. Woeginger The complexity of computing the Muirhead-Dalton distance. 282-284 2009 57 Mathematical Social Sciences 2 http://dx.doi.org/10.1016/j.mathsocsci.2008.11.005 db/journals/mss/mss57.html#DeinekoKW09