Retracts and homotopies for multi-maps
Tom 115 / 1983
                    
                    
                        Fundamenta Mathematicae 115 (1983), 9-26                    
                                        
                        DOI: 10.4064/fm-115-1-9-26                    
                                    
                                                                
                             
             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                         
                                                            