Modules for references/citations

Bibliography Module, aka Drupal Scholar (http://drupal.org/project/biblio)

Requires Taxonomy
Allows users to manage and display lists of scholarly publications. Includes import from and export to various standard bibliographic programs and formats. It is integrated with Taxonomy, but, unfortunately, not CCK —even so, the advantages usually outweight the disadvantages for bibliographic content.

Footnotes (http://drupal.org/project/footnotes)

Add automatically numbered footnotes to your posts. Independent of Bibliography, but works well with it.