On algebraic characterization of coercive linear partial differential operators with constant coefficients
Tom 49 / 1989
                    
                    
                        Annales Polonici Mathematici 49 (1989), 209-219                    
                                        
                        DOI: 10.4064/ap-49-3-209-219                    
                                    
                                                                
                             
             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                         
                                                            