| 'A planned announcement'? - Costello in Canada, September 1948 | Cunningham, Emma | Article in Journal | | 2002 |
| 60 years on: the "Southern Unionists", the Crown and the Irish Republic | Kenny, Mary | Article in Journal | | 2009 |
| Declaring the Irish republic : another view | Stanford, W. B. | Article in Book | | 1982 |
| Ireland 1949-73 : a closet member of the Commonwealth? | Wynne, Ben | Article in Journal | | 2020 |
| John A. Costello, 1891-1976 : compromise Taoiseach | Jordan, Anthony J. | Monograph or Collective Volume | Westport Books | 2007 |
| John A. Costello, 1948-51, 1954-7 | Lysaght, Charles | Article in Book | NA | 2025 |
| John Costello 'announces' the repeal of the External Relations Act | McCabe, Ian | Article in Journal | | 1992 |
| Leaving the Commonwealth | McCabe, Ian | Article in Journal | | 1998 |
| Notes on conversations | Mansergh, Nicholas, 1910-1991 | Article in Book | | 1997 |
| The credentials controversy : Australia, Ireland and the Commonwealth, 1950-65 | Kennedy, Michael (Michael J.)Lee, David | Article in Journal | | 2007 |
| The first coalition - 60 years on | Flynn, Kevin Haddick | Article in Journal | | 2008 |
| The reluctant taoiseach : a biography of John A. Costello | McCullagh, David | Monograph or Collective Volume | Gill & Macmillan | 2010 |
| To the declaration of the Republic and the Ireland Act, 1945-9 | Whyte, J. H. | Article in Book | | 2003 |