Discussiones Mathematicae - General Algebra and Applications
Discussiones Mathematicae - General Algebra and Applications > 2001 > 21 > 1 > 67-82
Discussiones Mathematicae - General Algebra and Applications > 2008 > 28 > 2 > 227-235
Discussiones Mathematicae - General Algebra and Applications > 2001 > 21 > 1 > 67-82
Discussiones Mathematicae - General Algebra and Applications > 2008 > 28 > 2 > 227-235