In March 2012, a definitive link was found between the death of a Gulf coral community and the spill.

They say there is no definitive link between merger activity and the falloff in spending on research.

"It is premature for investigators to draw a definitive link to the person or group responsible."

But once again, the report found no definitive link between the use of the antidepressants and these pregnancy outcomes.

After all, studies have so far failed to make a definitive link.

Doctors and scientists have declined to make a definitive link so far.

Neither did the reports establish a definitive link to Al Qaeda.

Despite the concerns of some local residents, in most cases researchers have yet to show any definitive link between cancer clusters and environmental factors.

But there is no way of making a definitive link.

Scientists have yet to find a definitive link between water quality and the recent bird deaths.