Short reviews of the papers listed below can be found in: Zentrallblat für Mathematik und Ihre Grenzgebiete, Springer (database at ICM/Poland) (ZMATH), Springer (original database) (ZMATH), Mathematical Reviews, AMS (MathSciNet), Current Mathematical Publications (CMP), INSPEC (password required) or ISI WEB of Science (available from 16 Polish universities).