Many thinkers have contributed their ideas concerning the nature of mathematics.

There is little evidence concerning the nature of this group.

Now if you could but be more explicit concerning the nature of your business.

There are those concerning the nature of the state and the extent to which governments can conserve the environment.

The book and film stand as a powerful revelation concerning the true nature of military service in wartime.

It is a story concerning the nature of life, death, and salvation.

The first scientific analyses concerning the nature of the discharge zone were now available.

Words alone were dangerous when they described ideas concerning the nature of Time.

There is a problem here concerning the nature of competition.

Among these developments were ideas concerning the nature and management of property.