| 'Put the saddle on the right horse' : Borklemore, county Wicklow, 1893 | O'Sullivan, Seán | Article in Book | | 2005 |
| A similarity in our causes | O'Sullivan, Seán | Article in Journal | | 1977 |
| Donagh MacCarthy, first earl of Clancarty, 1608-1665 | O'Sullivan, Seán | Thesis | | 1954 |
| Hugh Boulter, Lord Archbishop of Armagh | O'Sullivan, Seán | Article in Journal | | 1983 |
| Popular perceptions of the Royal Irish Constabulary during the land war in Galway | O'Sullivan, Seán | Article in Journal | | 1998 |
| Si monumentum requiris, circumspice | O'Sullivan, Seán | Article in Journal | | 1976 |