| relationship | 
                                    enum('supersedes', 'is-superseded-by', 'provides_post-cancellation_access_for', 'has-post-cancellation-access-in', 'tracks_demand-driven_acquisitions_for', 'has-demand-driven-acquisitions-in', 'has_backfile_in', 'has_frontfile_in', 'related_to') | 
                                    37 | 
                                     | 
                                     | 
                                    null | 
                                    
                                        
                                     | 
                                    
                                        
                                     | 
                                    relationship between the two agreements  |