The method 1, wherein {HEAD ~ the received data} for {TAIL ~ distribution} to at least one of the content servers comprises course material 
for
The method 1 , wherein { HEAD ~ the received data } for { TAIL ~ distribution } to at least one of the content servers comprises course material
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH