Oleg A. Prokopyev Sergiy Butenko Andrew C. Trapp Checking solvability of systems of interval linear equations and inequalities via mixed integer programming. 117-121 2009 199 European Journal of Operational Research 1 http://dx.doi.org/10.1016/j.ejor.2008.11.008 db/journals/eor/eor199.html#ProkopyevBT09