Include as much information as necessary to uniquely identify the source.
When in doubt about whether to include clarifying information in a citation, include it. For example, if no date is available in or on the source, use n.d. [no date] to indicate that. Be sure to check DeLib's Discovery or WorldCat to see whether catalogers have derived a publication date from other sources.
Cite the full title of a journal or magazine unless the style you use explicitly requires abbreviated journal titles (ACS and CSE styles, for example). Bibliographies and indexes often cite abbreviated periodical titles. To locate the full title use:
All that JAS: Journal Abbreviation Sources. Registry of Web resources that list or provide access to the full title of journal abbreviations or other types of abbreviated publication titles (e.g., conference proceedings titles). Selected online library catalogs that offer abbreviated title searching have also been included. In addition, access to full journal title directories or lists is also provided.
Why to cite: Give credit where credit is due. Cite your sources using one of the styles listed below or another style approved by the instructor. Knowingly representing the work of others as your own is plagiarism. (For details, see Cornell's Code of Academic Integrity).