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