| 'A planned announcement'? - Costello in Canada, September 1948 | Cunningham, Emma | Article in Journal | | 2002 |
| Declaring the Irish republic : another view | Stanford, W. B. | Article in Book | | 1982 |
| John A. Costello, 1891-1976 : compromise Taoiseach | Jordan, Anthony J. | Monograph or Collective Volume | Westport Books | 2007 |
| 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 |
| To the declaration of the Republic and the Ireland Act, 1945-9 | Whyte, J. H. | Article in Book | | 2003 |