Problems on semigroups
Tom 8 / 1961
                    
                    
                        Colloquium Mathematicum 8 (1961), 223-224                    
                                        
                        DOI: 10.4064/cm-8-2-223-224                    
                                    
                                                                
                             
             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                         
                                                            