On monotone unions of closed n-cells
Tom 23 / 1971
                    
                    
                        Colloquium Mathematicum 23 (1971), 65-68                    
                                        
                        DOI: 10.4064/cm-23-1-65-68                    
                                    
                                                                
                             
             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                         
                                                            