Ulrich Geske Armin Wolf Declarative Modelling and Efficient Optimization using Constraint Technology. 515-516 2008 GI Jahrestagung (2) conf/gi/2008-2 db/conf/gi/gi2008-2.html#GeskeW07 http://subs.emis.de/LNI/Proceedings/Proceedings134/article2139.html