On the integrability of the ergodic maximal function
Volume 73 / 1982
                    
                    
                        Studia Mathematica 73 (1982), 153-167                    
                                        
                        DOI: 10.4064/sm-73-2-153-167                    
                                    
                                                                
                             
             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                         
                                                            