3.5 Citing Sources

When Sources Must Be Cited – (A Checklist)

Information that always must be cited—whether web-based or print-based—includes:

  • Quotations, opinions, and predictions, whether directly quoted or paraphrased.
  • Statistics derived by the original author.
  • Visuals in the original.
  • Another author’s theories.
  • Case studies.
  • Another author’s direct experimental methods or results.
  • Another author’s specialized research procedures or findings.

If you use specific information of the type just mentioned, document it; otherwise, you could be plagiarizing. Better safe than lazy. By citing the source of your information, you point to an authority rather than ask your reader to trust your memory or what might appear to be your own idea. Even though you can recall a statistic or a description of a process, for example, citation of such information—if it came directly from a source—gives more credibility to your writing and underscores the accuracy, timeliness, and even the potential bias of your information. In short, be honest, smart, and safe.

Before we move into the specifics on how to properly cite your sources, this short (5:37) video offers insight on the importance of the subject. The principles discussed in this video are expanded upon in this chapter.

Integrating Source Material

In technical writing, integrating source material is a process of selection, extraction, and recontextualizing. Technical writing rarely relies on direct quotations, because the author’s exact wording is usually not as relevant as the data or information reported. Suppose you are writing a technical paper on mine safety, for example, and you encounter this material:

Since 1870, 121,000 mining deaths have occurred; 1.7 million lost-time injuries have been recorded since 1930. Historically, all of this has contributed to the public’s negative perception of mining safety and even helped to fuel the NIMBY mentality.

It is highly unlikely that you would quote these sentences directly, especially because some of the material is data and some is interpretation. The exact wording does not matter, but some of the material does, so your job is to extract only the relevant information, use it, and cite the source.

Similarly, there is no good reason to quote this sentence directly:

Acid mine drainage has been and continues to be a major problem generated by the mining of coal in Pennsylvania and elsewhere in the world.

In this instance, the information is so general that it need not even be cited, but neither should the sentence itself just be plucked out and plopped into your paper. Ideally, the information from the above sentence would simply end up as part of a sentence of your own creation such as this one:

This paper explores the three chief reasons why acid mine drainage continues to be a major environmental problem in Pennsylvania.

In this example, note how the relevant information is extracted from the source, without the need for citation, and note how the writer creates new context for the information.

Blending Source Material with Your Own Work

When working with sources, many students worry they are simply regurgitating ideas that others formulated. That is why it is important for you to develop your own assertions, organize your findings so that your own ideas are still the thrust of the paper, and take care not to rely too much on any one source, or your paper’s content might be controlled too heavily by that source.

In practical terms, some ways to develop and back up your assertions include:

  • Blend sources with your assertions. Organize your sources before and as you write so that they blend, even within paragraphs. Your paper—both globally and at the paragraph level—should reveal relationships among your sources, and should also reveal the relationships between your own ideas and those of your sources.
  • Write an original introduction and conclusion. As much as is practical, make the paper’s introduction and conclusion your own ideas or your own synthesis of the ideas inherent in your research. Use sources minimally in your introduction and conclusion.
  • Open and close paragraphs with originality. In general, use the openings and closing of your paragraphs to reveal your work—”enclose” your sources among your assertions. At a minimum, create your own topic sentences and wrap-up sentences for paragraphs.
  • Use transparent rhetorical strategies. When appropriate, outwardly practice such rhetorical strategies as analysis, synthesis, comparison, contrast, summary, description, definition, hierarchical structure, evaluation, hypothesis, generalization, classification, and even narration. Prove to your reader that you are thinking as you write.

Also, you must clarify where your own ideas end and the cited information begins. Part of your job is to help your reader draw the line between these two things, often by the way you create context for the cited information. A phrase such as “A 1979 study revealed that . . .” is an obvious announcement of citation to come. Another recommended technique is inserting the author’s name into the text to announce the beginning of your cited information. You may worry that you are not allowed to give the actual names of sources you have studied in the paper’s text, but just the opposite is true. In fact, the more respectable a source you cite, the more impressed your reader is likely to be with your material while reading. Suppose you note that the source is the NASA Science website, an article by Stephen Jay Gould, or a recent edition of The Wall Street Journal right in your text. In that case, you offer your readers immediate context without their having to guess or flip to the references page to look up the source.

What follows is an excerpt from a political science paper that clearly and admirably draws the line between writer and cited information:

The above political upheaval illuminates the reasons behind the growing Iranian hatred of foreign interference; as a result of this hatred, three enduring geopolitical patterns have evolved in Iran, as noted by John Limbert. First . . .

Note how the writer begins by redefining her previous paragraph’s topic (political upheaval), then connects this to Iran’s hatred of foreign interference, then suggests a causal relationship and ties her ideas into John Limbert’s analysis—thereby announcing that a synthesis of Limbert’s work is coming. This writer’s work also becomes more credible and meaningful because, right in the text, she announces the name of a person who is a recognized authority in the field. Even in this short excerpt, it is obvious that this writer is using proper citation and backing up her own assertions with confidence and style.

Anatomy of a Well-Cited Paragraph

Writing a paragraph with the sources properly cited can seem tricky at first, but the process is straightforward enough, especially when analyzing an example. Writing a good paragraph is really just a matter of thinking clearly about a topic you have researched and transferring that thinking to the page. To illustrate, a tidy sample paragraph follows, with the sources documented correctly in the author-year system. Next, the genesis of the paragraph is analyzed:

The millions of species of plants and animals on the earth have a phenomenal influence on the human species. Not only do they provide a substantial amount of our food, they are of great value in medicine and science. Over 60 percent of the purchases we make at the pharmacy contain substances that are derived from wild organisms (Myers 2008). Studies of plants and animals have led to discoveries in virtually all of the sciences, from biology and chemistry to psychology and astronomy (Wilson 2001). Furthermore, plants and animals are vital to the maintenance of our ecosystem. Their diversity and balance directly control food webs, nutrient diversity, supplies of fresh water, climate consistency, and waste disposal (Eberly 1988). Finally, many species act as barometers of our environment. The salmon, for example, is extremely sensitive to changes in the condition of the water in which it lives. Any abnormality in population or behavior of fish usually indicates some type of chemical imbalance in the water. The same is true of butterflies and their responses to the environment within prominent agricultural areas. Clearly, the millions of species of plants and animals in the world are vital to the continued thriving of the human population.

Now let’s walk through the paragraph and its use of sources. The first two sentences assert the author’s personal view about the value of the world’s species (a perspective shaped by his research, no doubt), which he is about to back up by using three recent sources. Next, the author cites a journal article (Myers) from which he extracted a statistic (“over 60 percent of the purchases we make at the pharmacy”). Without this source cited, the reader might believe that the author estimated loosely or simply relied on his memory for the statistic. The following source (Wilson) is cited because the paper’s author borrowed a general claim from a textbook by Wilson. At first, the author was unsure whether to cite the source, but he wisely decided that he should because he realized that he had, in fact, had Wilson’s book open to a particular page and referred to it as he wrote the sentence. The following source (Eberly) is cited because the author had browsed through a whole chapter of Eberly’s book to compose the list in the sentence, usually using Eberly’s exact section headings from the chapter as the list members. The final examples of the salmon and the butterfly were based directly on the author’s personal experience working at a fish hatchery for a summer, so documenting sources was not an issue. The fact that the author finds a way to tie this experiential knowledge in with his research is testimony to the fact that he is thinking as he writes the paragraph. He blends his sources, but he does not allow them to do the thinking for him. 

More evidence of the author’s control over his material resides in his transparent mid-paragraph transition sentence (beginning with “Furthermore”), his labeling of species as “barometers” of the environment a few sentences later, and his closing sentence, which wraps up the paragraph’s ideas neatly by making an affirmative and confident statement that backs up his topic sentence and examples.

Not every paragraph should look exactly like this, of course, but every paragraph should be written with the same kind of conscientiousness about how, when, and why the sources are cited.

Author-Year System: In-Text Citation

The author-year system of documentation is used more on the undergraduate level than at the graduate. Fields that have ties to the liberal arts, such as geography, human development, and political science, tend to favor the author-year system.

Your basic job when using this system is to indicate right in the text—in parentheses—the author(s) and year of publication of the reference you are citing. Since the citation becomes part of your sentence, you delay the appropriate punctuation until after the parentheses:

In recent decades, anthropogenic activities such as deforestation, desertification, and urbanization have significantly altered the land surface (Nicholson 2007).

Many writers identify the source as soon as they begin the reference, including the author’s name directly in the text and supplying only the year in parentheses:

Furlong et al. (2001) estimate that the first Mt. Erebus eruption . . .

If you use two or more articles written by the same author(s) in the same year, you distinguish between the documents in your text and on your references page by using an “a,b,c” system, providing an identifying letter after the year:

Toon (1989a) found evidence of . . .

When citing web-based sources in your text, you will often encounter sources with no author listed. Handle these cases just as you would when citing print sources—that is, if no author’s name is given in the original, offer the title of the web page, or the publication’s title, or the publisher’s name. If such a title is lengthy enough to be awkward, offer a clear shortened form of the title, with the goal of making it easy for us to find the source on the references page. In the following example, a document authored by a governmental agency is identified by a shortened form of its name:

Coordinated measurements planned in the framework of the original program should help to explain the apparent discrepancies in the data (PRIMO document, 1989).

Other In-Text Citation Practices

Slight but important mechanical differences exist among in-text citation practices, in particular when you are trying to conform to a specific style, such as MLA (Modern Language Association) or APA (American Psychological Association). For example, MLA style requires you to provide the page number of your citation in-text, but not the year, while APA style asks you to place a comma between author and year. Please feel welcome to explore all of these nuances for yourself if you wish, and recognize that some professors will insist that you conform to a particular style. When professors do not dictate a particular style, they will usually simply expect you to use the author-year or number system with consistency throughout the paper.

Remember, too, that journals within your field have already made informed decisions about which in-text citation practices they use. To settle on citation particulars, many writers model a journal in their field—mandatory, of course, if you submit material to a journal hoping for publication.

Want to read up on the specifics of various citation styles, in particular MLA and APA?

Check out: “Research and Citation Resources” article from Purdue’s Online Writing Lab (OWL)(link is external)

Author-Year System: References Pages

Following in-text citation of sources, of course, you are obliged to provide bibliographic information about your sources on a references page. Composing a references page is, for many writers, a painful process, particularly if they handled their references sloppily at the research stage. You simplify your task greatly by recording complete bibliographic information of your cited sources as you research, thus building your references page as you go. Some students wisely use notecards to keep track of their references, while others have a less formal system. As I cite sources in-text, I simply keep adding the complete bibliographic information to my references page right in my Word file for the paper; thus my references page is finished as soon as the last paragraph is.

As with in-text citation, reference page styles vary from one publication to another, but the fundamentals can still be expressed by the two simple categories of the author-year system and the number system. You could, of course, choose any respected magazine or journal in your field as a model for your references page and use it consistently, and this is often the easiest and most logical path to take.

Mechanics of the Author-Year System References Page

Using the author-year system, on your references page you typically provide the following information in the following order:

  • The names and initials of all authors, beginning with the last name of the first author listed, followed by a comma.
  • Year of publication, followed by a colon.
  • Title of the document or article being cited, with the key words capitalized. Quotation marks could be used around article titles.
  • Title of book, magazine, or journal, underlined or italicized, with journal titles abbreviated, followed by a period.
  • Publication information—for a book or privately published document, provide the publisher’s name and location, then the total number of pages, separated by commas; for a journal or magazine, provide the volume number in boldface, then a comma, then the page numbers of the article being cited.
  • The entire URL (if the source is a website), usually enclosed in brackets, followed by a period. Then provide either the last date the page was updated or the date that you accessed it, followed by a period. When citing a web document, typical bibliographic details, such as the page’s author, will often be unavailable. Therefore, skip the steps above as needed, but always provide the URL.

At times, some of the above information will be unavailable or sketchy, especially in relation to company brochures, maps, non-professional publications, and web sources. It is acceptable to omit unavailable information, of course, but when less information is available you might provide a short narrative description of a particular source.

Sample Author-Year System References Page

REFERENCES

Charlock, T.P., and V. Ramanathan, 1985: “The Albedo Field and Cloud Radiative Forcing Produced by a General Circulation Model with Internally Generated Cloud Optics.” J. Atmos. Sci., 42, 1408-1429.

“Drilling Probes Mediterranean Climate and Oceanography,” originally published in Earth in Space 8, May 1996. accessed May 22, 2001.

Ozick, B., 1987: The Physical Oceanography of the Mediterranean Sea. Bell Publishing Co. Austin, TX. 176 pp.

PRIMO document, 1989: Preparatory document on the development of PRIMO, an international research program in the western Mediterranean. Published by PRIMO, Inc., Paris. 29 pp.

Number System: In-Text Citation

Generally, the number system is favored in fields where you typically report experimental field or lab work. Technical fields such as materials science, aerospace engineering, and chemistry tend to favor the number system.

When you use the number system, your responsibility is to indicate in your text—either in parentheses or brackets—a number that corresponds to a source on your references page. The first source you cite in your text receives the number 1, the second number 2, and so on. If you repeat a reference to a source later in the text, it retains its original number—thus, all references to source number 4 receive a 4 after them in parentheses or brackets. You delay the appropriate punctuation until after the parentheses or brackets:

If the load on the thrust bearing can be decreased by some means, the life of the turbodrill can be significantly increased (1).

Many authors prefer to identify the source at the beginning of the reference, perhaps including the author’s name directly in the text:

Gould et al. (5) found a clear relation between. . .

The number system is especially handy for citing equations, because you can simply insert the citation number logically as you introduce the equation to avoid confusion with any other numbers:

The line’s slope is used in the following equation (7) to calculate. . .

Number System: References Pages

Following in-text citation of sources, of course, you are obliged to provide bibliographic information about your sources on a references page. Composing a references page is, for many writers, a painful process, particularly if they handled their references sloppily at the research stage. You simplify your task greatly by recording complete bibliographic information of your cited sources as you research, thus building your references page as you go. Some students wisely use notecards to keep track of their references, while others have a less formal system. As I cite sources in-text, I simply keep adding the complete bibliographic information to my references page right in my Word file for the paper; thus my references page is finished as soon as the last paragraph is.

As with in-text citation, reference page styles vary from one publication to another, but the fundamentals can still be expressed by the two simple categories of the author-year system and the number system. You could, of course, choose any respected magazine or journal in your field as a model for your references page and use it consistently, and this is often the easiest and most logical path to take.

Mechanics of the Number System References Page

Using the number system, on your references page you typically provide the following information in the following order:

  • The number of the reference, followed by a period.
  • The first initials and last names of all authors, followed by a comma.
  • Title of the article enclosed in quotation marks, followed by a comma.
  • Title of book, magazine, or journal, underlined or italicized, with journal titles typically abbreviated, followed by a period.
  • Volume numbers or editors—if citing a journal or magazine, provide the volume number in boldface, followed by the issue number in brackets; if citing a book with editors or volume numbers, provide the names of the editors or the volume numbers.
  • Publication information—for a book or privately published document, provide the relevant page numbers, then the publisher’s name and location (all separated by commas), then the year in parentheses, followed by a period; for a journal or magazine, provide the relevant page numbers of the article being cited, then the year in parentheses, followed by a period.
  • The entire URL (if the source is a website), usually enclosed in brackets, followed by a period. Then provide either the last date the page was updated or the date that you accessed it, followed by a period. When citing a web document, typical bibliographic details, such as the page’s author, will often be unavailable. Therefore, skip the steps above as needed, but always provide the URL.

At times, some of the above information will be unavailable or sketchy, especially in relation to company brochures, maps, non-professional publications, and web sources. It is acceptable to omit unavailable information, of course, but when less information is available you might provide a short narrative description of a source for clarity.

Sample Number System References Page

REFERENCES

1. M. Poulain and J. Lucas, “Optical Properties of Zirconium Tetrafluoride-Based Glasses,” Mater. Res. Bull. 10, 243 (1975). G. E. Rindone, “Influence of Platinum Nucleation on the Crystallization of Lithium Silicate Glasses,” J. Am. Ceram. Soc., 41 [1] 41-42

2. Gutzow and S. Toschev, “The Kinetics of Nucleation and the Formation of Glass Ceramics,” in Advances in Nucleation and Crystallization of Glasses. Edited by L.L. Hench and S.W. Frieman. American Ceramic Society, Columbus, OH, (1971). pp. 10-23.

3. C. Walker, “Kinetics of Nucleation and Crystal Growth in Glass Forming Melts in Microgravity.<http://searchpdf.adobe.com/proxies/0/34/70/56.html>(link is external). accessed May 10, 2001.

FAQs about Citing Sources

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