Assertion: racket's material | /r/AtLocation | boron
Facets:
Source sentences:
text: In the early 1980s, "graphite" (carbon fibre) composites were introduced, and other materials were added to the composite, including ceramics, glass fibre, boron, and titanium.
text: In the early 1980s, "graphite" (carbon fibre) composites were introduced, and other materials were added to the composite, including ceramics, glass-fibre, boron, and titanium.