On minimal regular digraphs with given girth
Tom 69 / 1970
                    
                    
                        Fundamenta Mathematicae 69 (1970), 227-231                    
                                        
                        DOI: 10.4064/fm-69-3-227-231                    
                                    
                                                                
                             
             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                         
                                                            