Assertion: classical music's opera | /r/HasProperty | king roger
Facets:
value: by ubu rex
type: OTHER
value: in the 20th century
type: TEMPORAL
value: by karol szymanowski
type: OTHER
value: by krzysztof penderecki
type: OTHER
Source sentences:
text: In the 20th century, other operas created by Polish composers included King Roger by Karol Szymanowski and Ubu Rex by Krzysztof Penderecki.