To call a referendum, he must obtain approval from parliament.

The two could form a government and, with a simple majority in parliament, call a referendum.

Eight cantons together can also call a referendum on a federal law.

Denmark, in turn, has promised to call a new referendum next May, but this is not simple.

You'll need a government with a majority that calls a referendum.

Under a law passed this year, Parliament must call a referendum if 100,000 citizens ask for it.

The President may decide to call a referendum on legislation "of great national significance".

"I've just been informed you're calling a referendum for total independence."

The Cabinet is also allowed to call a national referendum.

In response, the president called a referendum on a constitution for April 11.