Commutative algebra, singularities and computer algebra : [proceedings of the NATO advanced research workshop on commutative algebra, singularities and computer algebra ; Sinaia, Romania, 17 - 22 September 2002] - Herzog, Jürgen (Hrsg.); Advanced Research Workshop on Commutative Algebra, Singularities; Computer Algebra (2002 : Sinaia) (NATO science series. Series 2, Mathematics, physics and chemistry, 2003)