Either a single ester or {TAIL ~ a mixture} of {HEAD ~ esters} can be used as organic acid esters 
Either a single ester or { TAIL ~ a mixture } of { HEAD ~ esters } can be used as organic acid esters
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH