Here, {HEAD ~ the first voltage source V1} is {TAIL ~ an output} from a constant voltage circuit 
is
Here , { HEAD ~ the first voltage source V1 } is { TAIL ~ an output } from a constant voltage circuit
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH