Thereafter, the bids forming this combination can be declared {HEAD ~ the winning bids} of the auction, reverse auction or {TAIL ~ exchange} 
of
Thereafter , the bids forming this combination can be declared { HEAD ~ the winning bids } of the auction , reverse auction or { TAIL ~ exchange }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL