The current source provides {HEAD ~ constant currents IR1} and IR2 through {TAIL ~ resistors R1} and R2, respectively 
through
The current source provides { HEAD ~ constant currents IR1 } and IR2 through { TAIL ~ resistors R1 } and R2 , respectively
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH