Content management systems, Wordpress, Joomla and Drupal offer many features, frequently too many. However I've yet to find an easy way to create footnotes for citations without using either purpose built plugin, or either one with too much additional functionality, as a Latex editor would offer.
The middle ground is to use HTML superscript and anchors. While I wouldn't want to create pages of footnotes content in this fashion, it is useful for the occasional page which requires citations.
This page, Footnotes in HTML describes it better than I can, but the basics are below.
The HTML comprises of the text with a superscript link, and a corresponding anchor with the reference. Easy enough once you get the hang of it, and no plug is needed.
The link in the body of the text:
Text with a footnote.<sup><a href="#fn1" id="ref1">1</a></sup>
and the corresponding footnote at the bottom of the page:
<sup id="fn1">1. [Text of footnote 1]<a href="#ref1" title="Jump back to footnote 1 in the text.">↩</a></sup>