Every time someone talks about a referendum on an EU matter, look very very carefully indeed at precisely what question they're proposing to ask, and the circumstances in which they're proposing to ask it.
The game with referendums is always to deny the public the right to choose on any actual relevant question.
Imagine it were proposed that the EU modify its institutional arrangements in a way which is not supported by the general public in a particular member state, but that a tiny minority of vicious cranks, let us call them, say, Europhiles, favour this change. Those few in favour of the change can propose a referendum about something else, such as mere membership of the EU.
They do this time and time again. A few previous times are documented on my blog already.
And here they are, at it again with Greece: you're not allowed to have a referendum on the bailout package, only on Eurozone membership.
The effect of this is that the people get no say, whatsoever over the rules that affect their lives. Cui bono?