D. Sabin and E.C. Freuder.
Optimization methods for constraint resource problems.
In: Proc. of the AAAI'99 Workshop on Configuration, Orlando, July 1999.
Available at: http://wwwold.ifi.uni-klu.ac.at/~alf/aaai99/23Sabin.ps.
Readers of this
paper are warned that the solution given in this paper appears
to overlook the constraint that at most three cards can
be plugged into any one rack.
For the "correct" results, see page 147 of Ulrich John:
Configuration and Reconfiguration with Constraint-based Modelling
(In German: Konfiguration und Rekonfiguration mittels Constraint-basierter
Modellierung). DISKI 255. Akademische Verlagsgesellschaft, Berlin 2002. ISBN
3-89838-255-9.
Z. Kiziltan and B. Hnich.
Symmetry breaking in a rack configuration problem.
In: Proc. of the IJCAI'01 Workshop on Modelling and Solving Problems with Constraints, Seattle, August 2001.
Available at:
http://www.lirmm.fr/~bessiere/ws_ijcai01/kiziltan.ps.gz .