You have to run LaTeX at least twice to get a bibliography typeset. This is time consuming but the only way to see which references should be included in the document. Once the .bbl file exists you can edit this file for corrections or add/remove some references. This saves you from editing the databases and running LaTeX and BibTeX again but you should remember that changes in the .bbl file do not change the citations (e.g., the numbering) and will be defeated as soon as you run BibTeX again.