| Archive:Opera terminology (Restricted) + | 15:54:56, 15 April 2012 + |
| Archive:Operas + | 21:10:07, 21 November 2014 + |
| Archive:Operas (Investigation) + | 15:46:15, 15 April 2012 + |
| Archive:Operas (Public domain) + | 16:03:03, 19 March 2012 + |
| Archive:Operas (Restricted) + | 15:42:34, 15 April 2012 + |
| Archive:Operetta + | 21:10:10, 21 November 2014 + |
| Archive:Operetta (Investigation) + | 23:48:43, 10 October 2011 + |
| Archive:Operetta (Public domain) + | 15:55:48, 12 January 2012 + |
| Archive:Operetta (Restricted) + | 21:11:03, 12 January 2012 + |
| Archive:Operettas + | 20:54:49, 21 November 2014 + |
| Archive:Operettas (Investigation) + | 15:47:12, 15 April 2012 + |
| Archive:Operettas (Public domain) + | 15:32:29, 15 April 2012 + |
| Archive:Operettas (Restricted) + | 15:43:32, 15 April 2012 + |
| Archive:Oratorio + | 21:10:19, 21 November 2014 + |
| Archive:Oratorio (Investigation) + | 00:24:29, 11 October 2011 + |
| Archive:Oratorio (Public domain) + | 15:57:23, 12 January 2012 + |
| Archive:Oratorio (Restricted) + | 18:51:31, 12 January 2012 + |
| Archive:Oratorios + | 20:52:45, 21 November 2014 + |
| Archive:Oratorios (Investigation) + | 15:49:24, 15 April 2012 + |
| Archive:Oratorios (Public domain) + | 15:34:32, 15 April 2012 + |
| Archive:Oratorios (Restricted) + | 15:45:27, 15 April 2012 + |
| Archive:Organ repertoire + | 21:10:31, 21 November 2014 + |
| Archive:Organ repertoire (Investigation) + | 00:19:13, 11 October 2011 + |
| Archive:Organ repertoire (Public domain) + | 16:09:05, 12 January 2012 + |
| Archive:Organ repertoire (Restricted) + | 18:53:22, 12 January 2012 + |