On Star-Connected Flat Languages. - Barbara Klunder; Edward Ochmanski; Krystyna Stawikowska (Fundam. Informaticae, 2005)

Star-free Star and Trace Languages. - Edward Ochmanski; Krystyna Stawikowska (Fundam. Informaticae, 2006)

A Star Operation for Star-Free Trace Languages. - Edward Ochmanski; Krystyna Stawikowska (Developments in Language Theory, 2007)

On Star-Free Trace Languages and their Lexicographic Representations. - Krystyna Stawikowska; Edward Ochmanski (LATA, 2007)