The first two are online tools that can help you in creating citations for your in text citations and footnotes or bibliographies at the end of your papers. Simply enter or import the citation data, choose a citation style, and the tool generates the citation for you.
The second two are to help you create your references from your online search.
Note that the online tools are limited: they often only generate citations for the most commonly used resources, such as books and articles. They may not have an option, or generate an incorrect citation, for infrequently used formats, like videos, conference papers or interviews.
Son of Citation Machine: http://citationmachine.net/index2.php
BibMe – http://www.bibme.org/
When doing an EBSCO search:
When doing an OVID search: