1.   Frederick Herzberg put forward the two-factor approach to motivation after an extensive study of job attitudes among engineers and accountants.

2.   There have been no extensive studies of xenobiotic metabolising enzyme expression in colonic adenomas.

3.   Space and resources preclude an exhaustive or even an extensive comparative study in this work.

4.   An extensive study, for instance, argues that cigarette tax revenues are more than adequate to cover the medical costs created by smokers.

5.   An extensive new study has found that accidents are not the leading cause of sports deaths -- heart failure accounts for far more.

6.   Any health claim would require extensive studies to support it.

7.   A recently released extensive study says no.

8.   After a more extensive study, the Board of Trade reached the same conclusion.