A non-standard metric in the group of reals
Tom 50 / 1986
                    
                    
                        Colloquium Mathematicum 50 (1986), 241-248                    
                                        
                        DOI: 10.4064/cm-50-2-241-248                    
                                    
                                                                
                             
             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                         
                                                            