{HEAD ~ An umbrella structure} according to the invention comprises {TAIL ~ a cover}, a shaft, a notch, a runner, main ribs and stretchers 
comprises
{ HEAD ~ An umbrella structure } according to the invention comprises { TAIL ~ a cover } , a shaft , a notch , a runner , main ribs and stretchers
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH