Proposals, reports, and journal articles almost always contain references to earlier published work. Your work acquires credibility when you review the literature and show that your contribution extends from a solid foundation of respected research.
In citing sources and preparing an accurate reference section, you make it possible for readers to retrace your steps by locating and consulting the papers that informed your work. They may wish to assess your work in the light of previous contributions to the subject, or they may be reading for ideas to help them with new or continuing projects.
Preparing Citation and Reference Sections
In reporting the results of a literature review, you have two tasks. For one, you need to write citations to the earlier work you are reporting. These citations appear in the text, at the place where you have referred to the earlier work. For the other, you must prepare a reference section or bibliography with specific details about authorship, publication, editions, and dates for each citation. Reference sections appear at the end of the document.
In scientific and engineering fields, variants of two citation styles and at least one hundred reference styles are commonly used. The appropriateness of each is determined solely by the expectations of potential readers. Use whatever style you choose consistently throughout a document, but know that the particulars of style are established by convention and group practice. Even within specific fields, however, a variety of styles may be permitted.
Find out if style guidelines are available in your work setting or provided by your anticipated audience. If you are submitting an article for journal publication, check the journal for advice about preferred reference style. Consider purchasing the style manual of your professional society.
Several software packages are available for managing references. You create a database entry for each item, storing bibliographic information such as author, title, date, publisher, place of publication, volume, number, and page.
When you prepare the citations and reference section, you can choose from a menu of styles, and the software will automatically format your paper. If you revise your paper for a publication with different documentation standards, the software will reformat as necessary.
Citing References in Text In scientific and engineering writing, two broad styles are commonly used for citing earlier work. In one style, the authors name and year of publication are printed in the text, enclosed in parentheses. (Black 1996) The other style is based on a number, sometimes set on the line in parentheses or square brackets, sometimes set in superscript format. 
If the number appears in superscript format, it usually (but not always) refers to a footnote or endnote rather than to an item in a reference list.
In each case, the citation refers to more complete bibliographical information provided in a footnote or at the end of the document in the reference section.
If you are free to select a style for your in-text citations, consider these comparative features. Many readers prefer authors name/year of publication citations in a literature review. When names and dates are embedded in the text, readers immediately know what researchers you have consulted and can assess the currentness of your search.
Numbered references do not intrude on the text, so they are easier to skip over if you are reading strictly for research findings. If they are handled sequentially, though, numbered references may present problems when you add or delete anything.
Preparing a Reference List The precise bibliographic form for items in your reference list will be established by the style guide you select. For authors name/year of publication citations, references appear in alphabetical order. For numbered citations, references usually appear in the order in which you have referred to them, though some journals prefer alphabetical order in these cases as well.
Distinguish multiple items published by one author in the same year with lowercase alphabetic letters: (Wilde, 1997a; Wilde, 1997b).
Book. McClinrock, F. A. and A. S. Argon. 1966. The mechanical behavior of materials. Reading, MA: Addison-Wesley. Journal article. Ulmer, B. and H. Ishii. 2000. Emerging frameworks for tangible user interfaces. IBM systems journal. 39: 3:915 93 1. Article in an edited collection. Engelbart, D. C. 1960. A conceptual framework for the augmentation of mans intellect. In Computer-supported cooperative work, edited by I. Greif. San Mateo, CA: Morgan Kaufmann Publishers.
Report. Winward, A. H. 2000. Monitoring the vegetarian resources in riparian areas. Report No. RMRS-GTRA7. Ogden, UT: U.S. Department of Agriculture. Dissertation or thesis. Cavallo, D. 1996. Leveraging learning through technological fluency. Masters thesis. Massachuserts Institute of Technology Media Laboratory. Conference paper in proceedings. Fertwels, A., and M. Nossek. 1981. Sampling rate increase and decrease in wave digital filters. Proceedings, 6th IEEE symposium on circuits and systems, 839841. Chicago, IL: Institute of Electrical and Electronic Engineers.
Patent. Gershenfeld, N. September 21, 1993. Method and apparatus for electromagnetic non-contact position measurement with respect to one or more axes. U.S. Patent No. 5,247,261. Standard. American Society for Testing and Materials (ASTM). 1979. Standard for metric practice. PCN 06-503807- 41.
Citing Sources for Tables and Figures If you photocopy, scan, or otherwise reproduce a figure or table from another publication for inclusion in your document, you must credit the source. Even if you redraw the illustration but borrow significantly from the original, you need to cite the original author and publication. References to figures and tables can be identified by the word SOURCE (usually in small capital letters) and treated as an integral part of the artwork.
Citing Electronic Information Sources Though technology has advanced more rapidly than bibliographic practice, reference conventions have emerged for information gleaned from electronic media. The purpose of any reference section remains the same: To enable readers to locate and examine all documents referred to by the authors, including those that exist only as computer files.
In citing an electronic publication, your goal is to help readers to retrace your steps if they choose. Title, author, and date the material was written are crucial pieces of information, as they are in hard copy. It is helpful to include the publication medium (on- line database or CD-ROM, for example) and the name of the vendor or on-line publication service.
Details are not always available. Though a scrupulous Web site should include a page with month and day when it was last updated, such information is not always provided. For that reason, some researchers also include the date when they accessed the site referred to which they refer.
In general, personal e-mail is considered nonrecoverable information and is not included in a reference section, though it may have been mentioned in the text.
Abstract of a journal article from a database. Longo, N. and S. Langley, L. Griffan, and L. Elsas. May, 1995. Two mutations in the insulin receptor gene of a patient with leprechaunism. Journal of clinical endocrinology and metabolism, 80 (5) [Online abstracti. Medline Plus, National Library of Medicine. Item: UI 95263703. Article from an electronic journal. Bhandarkar, S. V., and S. H. Neau. December 15, 2000. Lipase-catalyzed enantioselective esterification of flurbiprofen with n-butanol [On-line Journal]. EJB Electronic Journal of Biotechnology, 3 (3). Available: http://www.ejb.org/content/vol3/issue3/fuII/3/.
CD-ROM. Aquatic Sciences and Fisheries Abstracts 19881994. [CDROM] Cambridge Scientific Abstracts. Compact Disc SP-160-0 10. Silver Platter. Available: http://www.silverplatter.com. Computer program. EndNote 4 (Word for Windows 2000 compatible format). [Computer program]. ISI ResearchSoft. Available: http:llwww.endnote.com. Web site. V. Gerasimov and W. Bender, Swings that think. Retrieved April 21, 2001 from the World Wide Web: http://vadim.www.media.mit.edu/srtfbat.html.
Paraphrasing and Quoting Ideas from Sources Even in documents explicitly designated as literature reviews, technical authors do not usually quote extensively from their sources. Rather, they summarize key points, restating ideas in their own words.
However, whether you quote exactly and enclose the borrowed phrases or sentences in quotation marks or you restate and summarize in your own language, you must still credit the source. Only when the ideas and information are considered common know