The outputs of {HEAD ~ the individual power sources} are responsive and proportional to {TAIL ~ individual input control signals} 
The outputs of { HEAD ~ the individual power sources } are responsive and proportional to { TAIL ~ individual input control signals }
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL