There are sound economic reasons why this now has to change.

They hadn't wanted to do that before for two very sound reasons.

Of course, there are sound reasons not to include such a rule.

There are sound legal reasons for this which I'm sure you will understand.

There are sound reasons for debate on national security and other issues.

She did not like these chickens, for a number of very sound reasons.

Now, here was a very sound reason for not entering the complex.

But the decision to do so should be based on sound economic reasons.

There are sound reasons for the development of this system.

Those are sound reasons, and taken together they support the intervention.