### Get variants of complex cube-root

I found-out that complex cube-root can have 3 variants (see http://en.wikipedia.org/wiki/Cube_root)

But if I try in SageMath to do

```
(-1)^(1/3)
```

SageMath return (-1)^(1/3). When I try

```
(-1)^(1/3).n()
```

SageMath gives me numerical approximation of the one root (not real)...

How I can get all variants of complex cube-root without numerical approximation?

Thanks! P.S. Sorry for poor English...