The source recording is not continuous, and its exact provenance has not been firmly established.

Establishing the exact provenance of Mr Werritty is a task that has so far defeated the best efforts of our columnar research staff.

The exact provenance of the 'Desert Rat' formation sign as worn on uniforms is still not entirely clear, and several different wartime variants exist.

It proved to be impossible to establish the exact provenance of the remains.

The only known specimen is from the Late Cretaceous of the Middle East, though its exact provenance is uncertain.

Its exact provenance is therefore uncertain.

No one knows the exact provenance of the wings.

Whatever its exact provenance, this particular vision was unsettling.

The exact provenance of the pagoda is unknown as no contemporary records of its origins survive.

It is uncertain what was the exact provenance of these four vehicles.