Joseph M. Pasia Karl F. Doerner Richard F. Hartl Marc Reimann Solving a Bi-objective Vehicle Routing Problem by Pareto-Ant Colony Optimization. 187-191 2007 conf/sls/2007 SLS http://dx.doi.org/10.1007/978-3-540-74446-7_15 db/conf/sls/sls2007.html#PasiaDHR07