According to Walker and Taylor (2006) there are five principles of referencing:

1. Intellectual property. “Using someone else’s ideas, words and phrases, or form of presentation without giving proper credit is plagiarism and can carry serious academic as well as legal penalties. Our conception of plagiarism is based on the notion of ownership of intellectual property. In the United States, the logic behind the principle of intellectual property is based on an economic model, stemming from the Constitution’s call to “promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries” (art. 1, sec. 8). … Beyond intellectual property laws, however, are considerations of ethics. Authors give credit for ideas borrowed from others as part of the process of knowledge building; we build upon— or refute— the ideas of others. In turn, our own ideas may become the foundation or building blocks for future work. Additionally, we give credit in the form of citation when we use the ideas of others simply because it is right to do so, thereby adding to our own credibility and authority as scholars.”

2. Access. References enable readers to find original sources to which the writer is referring.

3. Economy. Citations provide enough information to convey the source as briefly as possible.

4. Transparency. Reference styles should be understood by as many people as possible.

5. Standardization. Explicit standards for each reference style enable readers to understand the meaning of a citation in that style.

Neville (2007) discusses why referencing is important. He provides nine reasons, though acknowledges there are likely more:  Tracing the origins of ideas, Building a web of ideas, Finding your own voice, Validity of arguments, Spreading knowledge, An appreciation, Influences, Marking criteria, and to Avoid plagiarism. Plagiarism is defined in the University of Montana Student Conduct Code as "representing another person's words, ideas, data, or material's as one's own."

References
Neville, Colin. 2007. The Complete Guide to Referencing and Avoiding Plagiarism. New York: Open University Press.
University of Montana. 2013. University of Montana Student Conduct Code. Missoula, MT: University of Montana.
Walker, Janice R., and Todd Taylor. 2006. The Columbia Guide to Online Style. New York: Columbia University Press.

RefWorks allows you to manage your research and format citations. Use the web-based software to: create a personal database to keep track of your research articles, documents, websites, etc.; import citation information from a variety of resources into your database; generate a bibliography in a variety of styles (e.g., Chicago); and add in-text citations to a paper. You can also upload and annotate documents.