The dendritic structures comprise linkers and branch groups covalently bonded to each other in {HEAD ~ any} of {TAIL ~ various structural combinations} 
The dendritic structures comprise linkers and branch groups covalently bonded to each other in { HEAD ~ any } of { TAIL ~ various structural combinations }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL