Still, the source of the music could not be traced.

The source of the story was traced back to 4chan.

You get a line on it, we can trace the source.

Officials were still trying to trace the source of the attack.

He still could not trace the source, but it was there.

"The biggest problem people have is trying to trace the source," he said.

Once again the source may be traced to a high level of environmental stimulation.

And it is not that hard to trace the source of the transformation.

Why have you not been able to trace the source of this disease?

The source of the outbreak was traced back to the growing fields in California.