You must always cite information you use from other sources for the following reasons:
1. You need to let the reader or your instructor know the original source of information. Citing sources strengthens your paper and lets your instructor know that you did the work.
2. Citing is a service to the reader. The reader may be stimulated by a reference you have used in your works cited page and will be able to identify and access the sources you have used for his/her own use.
3. You want to give credit to the person whose ideas you have used.
For help with citing sources consult the following citation style guides available online:
Some databases will automatically generate a citation in MLA and other formats. Others will only provide the basic information, and it's up to you to do the formatting. Look for links like "Cite" or "How to cite" within the databases and on article pages. Also check the top and bottom of the page or article for citation info.
Warning: Most of the citations in databases, web services, etc., are produced automatically using a computer algorithm. That means that if the data is incorrect, the resulting citation is incorrect. You have the final responsibility of checking that the citation is fully correct using the guidelines provided by your professor (or publisher).
The following collections of databases will provide citations into rough versions of standard citation styles. Always check details like capitalization, dates, and page numbers.