Hans-Jörg Kreowski Sabine Kuske Communities of Autonomous Units for Pickup and Delivery Vehicle Routing. 281-296 2007 AGTIVE http://dx.doi.org/10.1007/978-3-540-89020-1_20 conf/agtive/2007 db/conf/agtive/agtive2007.html#KreowskiK07