Assertion: woolly mammoth's tusk | /r/HasProperty | articles of trade
Facets:
value: for at least 2,000 years
type: TEMPORAL
value: in asia
type: LOCATION
Source sentences:
text: Woolly mammoth tusks had been articles of trade in Asia long before Europeans became acquainted with them.
text: Mammoth tusks have been an article of trade for at least 2,000 years.