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