DW: After the Greeks voted "No" in Sunday's referendum, what can we expect to see over the next few days?

Bert Van Roosebeke: I think what we are going to see is that the eurozone will try to reach a deal again with the Greek government. The Greeks need money and they need it now. The easiest way for them to get it is to try to negotiate a new contract with the eurozone. The problem is that there is only a very short time to reach an agreement. On July 20, Greece has to pay back around 3.5 billion Euros to the European Central Bank.

They don't have the money, so they will either get it from the eurozone or they are not going to be able to repay the ECB. And if they're not able to do that, the European Central Bank is not going to be able to sustain the emergency credits to the Greek banks, which would mean that the banks go bankrupt from one day to another on July 21.

But it's going to be very difficult to find a compromise, I think, after the people in Greece have said no to the conditions in the old program.

Looking ahead a little, what can we expect from Greece and from the other members of the eurozone in the coming weeks and months?

The eurozone has to decide whether it wants to give Greece another chance and try to negotiate another contract. The Greek government has to decide under which conditions it would be willing to accept this program.

There are always going to be conditions. And they have to figure out at which point to say "This is going too far for us" and rather risk a Grexit. The possibility for a Grexit has definitely got bigger than it was last week.

It's very open whether a solution [that could keep Greece in the EU] will be found or not. I think it very much depends on the behavior of the new Greek finance minister in the negotiations.

Has the referendum strengthened Tsipras?

It has definitely strengthened him at home - for the Greeks he's the right guy to be prime minister. Whether it has strengthened him for negotiations in Brussels is a totally different story. A lot of other eurozone members think he has gone too far.

It's legitimate to discuss whether you have democratic support in Greece for these reforms. But the other member states also have to explain to their taxpayers why they keep giving so much money to Greece.

Looking ahead to the next couple of years, what kind of consequences do you think the referendum and the lead-up to it will have for the European Union in the long run? Do we have to worry about a domino effect?

I don't think other countries will follow the same trajectory - you have to see Greece as a very stand-alone case. Obviously, after all these years of negotiations and aid packages and what else went down, the relationship between Greece and the European Union is really not healthy at the moment. I think it's not something you can compare with any other member state of the EU. So I believe it's mainly a Greek problem and not a problem of the European Union.

The thing is that countries like Spain, Portugal and Ireland have put into practice the reforms that the European Union, the European Central Bank and the IMF have demanded from them. While they're not over the hill yet, they're doing much better and there's good reason to think they're not going to get into such a crisis again.

Of course, the reforms weren't very popular in these countries. But it's always going to be difficult, because the perception in these countries is that somebody from the outside, from Brussels, is coming in and telling elected governments what to do. And that's far from ideal.

One possible consequence is that the eurozone will become much more economically integrated, that we'll have an economic government trying to avoid such crises. There are some politicians who want that.

But there are also others who say that this is exactly what we don't need, that we need competition among member states. Then we'd have a battle to be strong, which they say the best way to remain vigilant and making good economic policies. It's an open question.

Bert van Roosebeke is a financial markets expert with Germany's Centre for European Policy, and has worked with the German central bank, the Bundesbank.