The authors would like to thank Jerzy Dudek for his hospitality
during their stay at the Institut de Recherches Subatomiques
in Strasbourg, where part of this work was done. This research was
supported in part by the Polish Committee for Scientific Research
(KBN) under Contract No. 5 P03B 014 21, by the Foundation for Polish
Science (FNP), by the French-Polish integrated actions programme
POLONIUM, by the U.S. Department of Energy under Contract Nos. DE-FG02-96ER40963 (University of Tennessee), and DE-AC05-00OR22725
with UT-Battelle, LLC (Oak Ridge National Laboratory), and by the
computational grant from the Interdisciplinary Centre for
Mathematical and Computational Modeling (ICM) of the Warsaw
University.