| Sg. indefinite | referendum |
| Sg. definite | referendummet |
| Pl. indefinite | referendummer; referenda |
| Pl. definite | referendummerne; referendaene |
| Sg. indefinite | referendums |
| Sg. definite | referendummets |
| Pl. indefinite | referendummers; referendas |
| Pl. definite | referendummernes; referendaenes |