Ubu Rex
... that the Polish composer Krzysztof Penderecki co-wrote the German libretto of Ubu Rex, his only opera buffa, based on the French play Ubu Roi?
... that the Polish composer <a href="./Krzysztof_Penderecki" id="mwBm8" rel="mw:WikiLink" title="Krzysztof Penderecki">Krzysztof Penderecki</a> co-wrote the German libretto of <i id="mwBnA"><b id="mwBnE"><a href="./Ubu_Rex" id="mwBnI" rel="mw:WikiLink" title="Ubu Rex">Ubu Rex</a></b></i>, his only <a href="./Opera_buffa" id="mwBnM" rel="mw:WikiLink" title="Opera buffa">opera buffa</a>, based on the French play <i id="mwBnQ"><a href="./Ubu_Roi" id="mwBnU" rel="mw:WikiLink" title="Ubu Roi">Ubu Roi</a></i>?