Assertion: ufo | /r/HasSubevent | investigations over the years
Facets:
value: over the years
type: TEMPORAL
Source sentences:
text: UFOs have been subject to investigations over the years that varied widely in scope and scientific rigor.
text: UFOs have been subject to investigations over the years that varied widely in scope and scientific rigor.
text: UFOs have been subject to investigations over the years that varied widely in scope and scientific rigor.
text: UFOs have been subject to investigations over the years that varied widely in scope and scientific rigor.
text: UFOs have been subject to investigations over the years that varied widely in scope and scientific rigor.
text: UFOs have been subject to investigations over the years that varied widely in scope and scientific rigor.
text: UFOs have been subject to investigations over the years that varied widely in scope and scientific rigor.
text: UFOs have been subject to investigations over the years that varied widely in scope and scientific rigor.