No previous study had given a figure, which amounts to $1.3 billion today.

This result is consistent with a previous study from 2008.

This is consistent with previous studies in 1977, 1988, and 2008.

This is consistent with previous studies in 1990 and 2008.

The most recent published data was a review of 15 previous studies.

This result is in line with previous studies which used under 20,000 pages.

But she said of previous studies, "I just don't think the data were there."

In this study they found very similar results to previous studies that have been conducted.

This result is in good agreement with a previous study performed during 1980.

Sometimes, a researcher can use data from previous studies as the basis for new work.