| Fitzwilliam accounts, 1560-5. (Annesley Collection) | | Monograph or Collective Volume | The Stationery Office [for the Irish Manuscripts Commission] | 1960 |
| Fitzwilliam in lreland, 1588-94 | Lawlor, Sheila | Article in Journal | | 1974 |
| Ireland under the Tudors : with a succinct account of the earlier history. 3 vols. | Bagwell, Richard | Monograph or Collective Volume | Longmans, Green | 1885 (v. I & II)
1890 (v. III) |
| The deputy's defence: Sir William Fitzwilliam's Apology on the outbreak of the Nine Years War in Ireland | Morgan, Hiram | Article in Journal | | 2014 |