{TAIL ~ SELEX} is an acronym for Systematic Evolution of Ligands by {HEAD ~ EXponential enrichment} 
{ TAIL ~ SELEX } is an acronym for Systematic Evolution of Ligands by { HEAD ~ EXponential enrichment }
TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD