In another aspect, the operational amplifier further comprises means, connected to the output, for pushing the output high and {TAIL ~ means}, connected to the output, for pulling {HEAD ~ the output} low 
In another aspect , the operational amplifier further comprises means , connected to the output , for pushing the output high and { TAIL ~ means } , connected to the output , for pulling { HEAD ~ the output } low
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH