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