| Abstracts of Chancery inquisitions of the seventeenth century for counties Fermanagh and Monaghan | Schlegel, Donald M. | Monograph or Collective Volume | Clogher Historical Society | 2008 |
| An index to the Insurgents of 1641 in the county Fermanagh depositions | Schlegel, Donald M. | Article in Journal | | 2004 |
| An index to the rebels of 1641 in the county Monaghan depositions | Schlegel, Donald M. | Article in Journal | | 1995 |
| Eastern Ulster origins in the Fermanagh genealogies: O'Monaghan, the Manaig, and St Ronan; Magarraghan, Lisgoole, and St Aed | Schlegel, Donald M. | Article in Journal | | 2010 |
| Lease abstracts for the Clones estate, Co. Monaghan | Schlegel, Donald M. | Article in Journal | | 2003 |
| Mac Domhnaill Clainn Ceallaigh | Schlegel, Donald M. | Article in Journal | | 2005 |
| Passengers from Ireland : lists of passengers arriving at American ports between 1811 and 1918 | Schlegel, Donald M. | Monograph or Collective Volume | Genealogical Publishing | 1980 |
| Scots Clan Donald in Dartree and Monaghan baronies | Schlegel, Donald M. | Article in Journal | | 1999 |
| Sir Brian and Lady Mary MacMahon | Schlegel, Donald M. | Article in Journal | | 1996 |
| Sliocht Lachlain Maguire (1300-1600). Ecclesiastics of the Erne | Schlegel, Donald M.
| Article in Journal | | 2013 |
| The Barton estate and Lough Bawn in county Monaghan | Schlegel, Donald M. | Article in Journal | | 1995 |
| The MacDonnells of Tyrone and Armagh : a genealogical study | Schlegel, Donald M. | Article in Journal | | 1980 |
| The origin of the three Collas and the fall of Emain | Schlegel, Donald M. | Article in Journal | | 1998 |
| The plundered tates : Cahill Duff O Connally and the bishop's land in Clones parish | Schlegel, Donald M. | Article in Journal | | 1991 |
| The Sheridans untangled | Schlegel, Donald M. | Article in Journal | | 2016 |
| Where was Rath Breasail's Sliab Beatha? | Schlegel, Donald M. | Article in Journal | | 2012 |