Articles, e.g. inflated sports balls made of {HEAD ~ these alloys} of polyurethanes and {TAIL ~ rubbers} have surprisingly low air permeability and improved resiliency 
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Articles , e.g. inflated sports balls made of { HEAD ~ these alloys } of polyurethanes and { TAIL ~ rubbers } have surprisingly low air permeability and improved resiliency
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH