Can you re-reference an endnote number in a research paper?

I'm writing a research paper, and I only plan to use about 8 sources. Now, I reference a source early in the paper, let's call that endnote #2. I then reference sources 3 and 4, but if I want to go back and re-reference the same page of number 2, do I put #2 again, re-list the source or not reference anything at all?

Can you re-reference an endnote number in a research paper?
No, continue counting but when you have your endnotes page at the end of the paper, do something like this





1. Author,title,publisher,page


2. Author,title,publisher,page


3....


4....


If 5 is the same book as 2, do this(even if it's the exact quote):





5. Author's last name, page.
Reply:In the end-note format, you would just give the same reference again and still give it #2. Don't leave a reference out if you took any information or ideas from a source--even if you put it in your own words.
Reply:what doug said