| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | referendum [prep] whether [to-vb] | 6 |
|
| 2 | referendum [prep] whether [verb] | 6 |
|
| 3 | referendum on whether [verb] | 6 |
|
| 4 | referendum on whether [verb] | 6 |
|
