Assertion: crack | /r/HasProperty | american song
Facets:
value: in the early 1970s
type: TEMPORAL
Source sentences:
text: Jimmy Crack Corn" or "Blue Tail Fly" is an American song which first became popular during the rise of blackface minstrelsy in the 1840s through performances by the Virginia Minstrels.
text: Crack the Sky is an American progressive rock band formed in Weirton, West Virginia, in the early 1970s.