{HEAD ~ The above mentioned spherical agglomerates} of {TAIL ~ hydroxyapatite microparticles} will be referred to hereinafter simply as the HAP sphere 
of
{ HEAD ~ The above mentioned spherical agglomerates } of { TAIL ~ hydroxyapatite microparticles } will be referred to hereinafter simply as the HAP sphere
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH