The only difference between endnotes and footnotes is that endnotes are placed at the end of the text (after the conclusion part but before the bibliography section) instead of being placed at the end of each page as for the footnotes. Hence, footnotes and endnotes are the same on the basis of content format.
Now, if your source appears more than once but on a different page number: you should definitely use the “Ibid.” standard if the source is repeated directly after its previous inclusion or the “op.cit.” (if it’s a book) or “loc.cit.” (if it’s an article) standard if the source was already mentioned but not in the last endnote prior to the one you are actually including.
Here are some examples (Morstado’s reference was created for the purpose of explaining how to include endnotes; his article does not exist in reality):
Example A: using three different sources for your paper: two books from Radford and one article from Morstado… 1- Robert Radford, Roman History, Morrisville: Lulu, 2007, p. 65.
Since it is the first time this Radford book is mentioned in your endnote section, the entire reference must be included.
2- Ibid., p. 67.
Ibid. is used because it is the same source as endnote 1 but the page number is different.
3- Enriqué Morstado, “Laughing in Theaters”, in Best Laughing Locations, San Salvador: Why Corporation, 2002, p. 11.
Since it is the first time this Morstado article is mentioned in your endnote section, the entire reference must be included.
4- Radford, op.cit., p. 69.
Op.cit. is used because it is a book and refers to endnote number 1.
Idem. is used because endnote 4 is exactly the same as endnote 5. Idem. means “Identical”.
6- Morstado, loc.cit., p. 15.
Loc.cit. is used because it is an article and refers to endnote number 3.
7- Ibid., p. 16.
8- Robert Radford, Cognition Guide, Morrisville: Lulu, 2007, p. 162.
P.S.: be careful, this is another, different, Radford book that appears in your endnote section.
9- Morstado, loc.cit., p. 20.
10- Radford, Cognition Guide, p. 101.
To avoid confusion between the two distinct Radford books mentioned previously, you must indicate the author’s name, the exact book title and, finally, the page number.
11- Radford, Roman History, p. 79.
Example B: using a single source for your paper…
1- Robert Radford, Cognition Guide, Morrisville: Lulu, 2007, p. 65.
2- Ibid., p. 50.
5- Ibid., p. 55.
6- Ibid., p. 60.