{HEAD ~ Resistors R} located between {TAIL ~ the non inverting terminals} of op amps 68 and 70 to voltage sources V2 provide balanced impedences to the op amp terminals 
located between
{ HEAD ~ Resistors R } located between { TAIL ~ the non inverting terminals } of op amps 68 and 70 to voltage sources V2 provide balanced impedences to the op amp terminals
HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH