A number of researchers have made great contributions to tackle this problem.

It has more than doubled its number of researchers, to 32,000, from 13,900 six years ago.

A small but growing number of researchers are calling on it.

A number of researchers are betting that the answer is yes.

The novel has been subject to treatment by a number of literary researchers.

Religion and happiness have been studied by a number of researchers.

A number of Japanese researchers consider 100,000-200,000 to be an approximate value.

Indeed, the association itself was questioned by a number of researchers.

This hypothesis is supported by a number of known researchers.

A number of Japanese researchers consider 100,000-200,000 to be an accurate estimate.