Is there a unified way to footnote? I keep sifting around online and there seems to be a variety of different footnote methods.


I want to make proper citations for each:

http://www.britannica.com/EBchecked/...943/Napoleon-I

http://library.brown.edu/cds/napoleon/time7.html

http://www.napoleon-series.org/milit..._chapter5.html

http://jonathangifford.com/leadershi...exile-in-elba/

https://books.google.com/books/about...AAAAMAAJ&hl=en


Please show how each would be written out.
The last one is the book the rest are online resources. Which I hope are credible this is a college level history essay.

Also, what should I do with the footnote when I am quoting the same source over again but it's in a different section of the same web recourse. should I put the same footnote twice or is there another method to this?

Thank you