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