found: Work cat.: Moravec, Paul. The king's man : an opera in one act, 2013.
found: Sheng, Bright. The song of Majnun : opera in one act, ℗1997.
found: Menotti, Gian Carlo. The boy who grew too fast : a one-act opera for young people, 2001.
found: Donizetti, Gaetano. Betly : opera comica in un atto = opera comica in one act, ©2010.
found: Paul Hindemith website, Aug. 18, 2017:Life & work > Biography > 1918-1927 > One-Act operas (Hindemith's triptych of one-act operas Mörder, Hoffnung der Frauen, Op. 12 (based on Oskar Kokoschka), Das Nusch-Nuschi, Op. 20 (based on Franz Blei) and Sancta Susanna, Op. 21 (based on August Stramm) are considered the epitome of his Expressionism)
found: One Act Opera Festival 2005 website, Aug. 18, 2017(4 One Act Operas; Barber's The Hand of Bridge; Menotti's The Old Maid and the Thief; Mozart's The Impresario; Puccini's Sister Angelica)
found: Wikipedia, Aug. 18, 2017(Category: One-act operas. This category contains operas which are specified in their libretto as having only one act. However, the number of acts is not necessarily an indication of the length of the opera. While most one-act operas have a relatively short running time (under 90 minutes), this is not always the case. For example, the one-act opera Das Rheingold has an approximate running time of 2 hours, 35 minutes)
