Publication Manual of the American Psychological Association by 
MLA Handbook by Citation searching, sometimes called cited reference searching, refers to finding articles that have cited a previously published older work (i.e. following research forward). Citation searching can also include looking at the citations within a paper (i.e. the Reference List) to trace research backwards.
The number of times a paper is cited in the work of others can be an indication of its usefulness. Through citation searching, you can discover how a known idea or innovation has been confirmed, applied, improved, extended, or corrected. Citation analysis can also be used to identify emerging areas of research, identify a field's leading researchers and to assess research output.
CREATION MOVES FORWARD IN SCIENTIFIC PUBLICATION
RESEARCH MOVES BACKWARD
The Kettering database Web of Science has a 'Citation Network' box next to each article. This gives a snapshot of how many times the article was cited (forward citation searching) and how many cited references the article contains (backward citation searching.)
The Citation Map below shows a visualization of both backward and forward citation searching. Note that only articles included inside Web of Science are counted.
CITATIONS
The in-text reference that gives brief details (author, date, page) of the source you are quoting or referring to. This citation corresponds with the full details of the work (title, publisher, etc) given in your reference list or bibliography, so that the reader can identify and/or find the source.
REFERENCE LIST
A list of references at the end of your paper that includes the full information for your citations so that the reader can easily identify and retrieve each work (journal articles, books, webpages, etc). Your reference list contains all the items you have cited or directly quoted from.
BIBLIOGRAPHY
A list of works you have consulted for your paper, but not cited in the Reference List. Works should be listed in alphabetical order by author and laid out in the same way as items in your reference list. If you can cite from every work you consulted, you will only need a reference list.
Always check the guidance you are given for your research paper to find out if you are expected to submit work with a reference list and a bibliography.
Zotero collects all your research in a single, searchable interface. You can add PDFs, images, audio and video files, snapshots of web pages. Zotero automatically indexes the full-text content of your library, enabling you to find exactly what you're looking for.
RefWorks is web-based bibliographic software that enables you to organize your research, include citations while you write your paper, build a bibliography in a variety of formats, import references from many data sources, and create bibliographies in different document formats (Word, RTF, HTML, etc.).
Mendeley is a free reference manager and academic social network that can help you organize your research, collaborate with others online, and discover the latest research in your field
Citeulike is a free service for managing and discovering scholarly references.
ReadCube is a free desktop and browser-based program for managing, annotating, and accessing academic research articles
EndNote Basic is the free version of the popular reference software. Features storage for up to 50,000 references, the 20 most popular bibliographic styles, and 2GB of file storage.