@phdthesis{Cardoso06,
   author = {Pedro Jorge {Sequeira Cardoso}},
   title = {Ant Colony Algorithms for Multiple Objective Combinatorial Optimization.
   Applications to the Minimum Spanning Trees Problems},
   school = {Department of Applied Mathematics, University of Seville},
   address = {Spain},
   month = {December},
   year = {2006}
}