The Reference Checker is an online software program I wrote that helps find problems with the references in academic papers. It is completely free to use (for non-commercial purposes), which means that students and academics who write research papers, articles, books, etc. may use it at any time to check their work.
What the Reference Checker does is to find all of the citations in your paper, as in Bomburger (2004), and compare them to the bibliography (references section), where those works are referenced, to make sure that (a) no works are missing from the bibliography, and (b) no works in the bibliography go uncited in the paper. Importantly, it catches cases in which you have mistyped the reference (as in Bomberger 2004, or Bomburger 2003); you would be surprised how often this happens. In fact, I have very rarely seen a paper that had no reference errors whatsoever.
Feel free to give it a try: