Assertion: free substitution | /r/HasProperty | implemented
Facets:
Source sentences:
text: The one-platoon system was largely abolished in the 1940s but aspects of it remained in force in college football until the 1960s, at which time total free substitution was implemented.)
text: The one-platoon system was largely abolished in the 1940s but aspects of it remained in force in college football until the 1960s, at which time total free substitution was implemented.)