With Avida, digital organism research has begun to be accepted as a valid contribution to evolutionary biology by a growing number of evolutionary biologists.

The paper concludes that the Lancet survey, "cannot be considered a reliable or valid contribution towards knowledge about the extent of mortality in Iraq since 2003."

After all, writing a book can be as valid a contribution to society as raising a child, especially in this overcrowded world of ours.

There are valid contributions of blacks to history and science, and we can talk about them.

Independent schools, such as Eton, are making a valid contribution to local state education, says Matthew Burgess.

Besides, Sunny, Theach and Brassner have valid contributions to make within the context of the galaxy.

Informed conjecture can make an equally valid contribution and this thought-provoking book may well lead to the revision of established theories of classical architecture.

I think that every Member State has a sufficient number of qualified people who can make a valid contribution to the EU.

Such agreements can certainly make a valid contribution to defining and solving problems, but they are not the final answer.

Opportunities now exist for Senior Technicians to make a valid contribution in two specific areas of this important field of research.