Discussiones Mathematicae - General Algebra and Applications
Discussiones Mathematicae - General Algebra and Applications > 2002 > 22 > 1 > 47-71
Discussiones Mathematicae - General Algebra and Applications > 2005 > 25 > 1 > 39-87
Discussiones Mathematicae - General Algebra and Applications > 2002 > 22 > 1 > 47-71
Discussiones Mathematicae - General Algebra and Applications > 2005 > 25 > 1 > 39-87