2. In-text citations
3. Citation list
4. Additional information
Why Should I Reference?
References are used to record or document the source of each piece of information in your paper obtained from other researchers and writers. If you fail to document information that is not your own, you have committed plagiarism, a form of stealing.
What Should I Reference?
You must reference all direct quotations; paraphrases of material; and summaries of opinions, ideas and interpretations obtained from other sources. If you fail to reference your information, you will be criticized for making statements that appear to be unsupported by evidence. It is not necessary to document information that is common knowledge (i.e., found in more than five sources), but remember that it is always better to overdocument than to underdocument.
You may be concerned that, if you reference too much, your instructors will think the paper is not your own work. That is not so. The method of organization is yours, as well as the purpose which ties the material together, the topic sentences, concluding sentences, analytical and evaluative comments which allow the reader to make sense out of the reference material, and probably most of the introductory and concluding paragraphs.
What Style Should I Use?
Always ask the professor which documentation style is required for the assignment. Styles can vary greatly between journals even within one scientific field. If no specifics are given, this Fastfacts can serve as a guide to one of the standard formats, described in Scientific Style and Format: The CBE Manual for Authors, Editors, and Publishers (known as the CBE style), used in all scientific disciplines related to experimental and observational science (including but not limited to physical sciences, mathematics, and life sciences).
How Do I Reference?
The CBE style uses either the Name-Year (N-Y) system or the Citation-Sequence (C-S) system for referencing. You will need to choose one of these systems for your paper and be consistent:
- The Name-Year system includes the author and year in parentheses within the text, and lists the references in alphabetical order within the Reference List.
- The Citation-Sequence system uses a number for each citation within the text, and entries in the Reference List are listed numerically according to the order of their inclusion within the text.
The disadvantage of the C-S system is that a reference added later in the writing process will require renumbering of all references in the list and within the text. However, an advantage is that the inclusion of superscript numbers as in the C-S system does not interrupt the flow of text as much as does a series of name-year citations within a sentence. (Note: Footnotes or endnotes in CBE style can be used for content that supplements or amplifies important information in the text, or for copyright permission.)
This handout provides examples of the CBE format for citations within the text (see "In-Text Citations") as well as for your references (see "Reference List") for the N-Y system.
A. In-Text Citations
In-text citations (also called parenthetical references) include the author's last name and the year of publication. These citations can be included within a sentence in various ways, but you should always keep them as close as possible to the relevant title, word, or phrase. Avoid placing citations at the end of long clauses or sentences, because the concept being referenced may be unclear.
- At the end of the sentence in parentheses:
This hypothesis was tested (Smith 1970).
- As part of the sentence, using the parentheses to include whatever reference information is not in the sentence:
Smith (1970) tested this hypothesis; OR
Smith's (1970) study tested this hypothesis; OR
In 1970, Smith tested this hypothesis.
If you include the titles of works within the text of your paper, use "double quotation marks" for the title of an article or chapter, and italics for the title of a periodical or book.
The following list explains what information needs to be included for various situations in a N-Y citation. These formats apply to both electronic and print sources.
ONE OR TWO AUTHORS
... was tested (Smith 1970).
... for measurement (ISO 1979).
... (Elias and Williams 1981).
THREE OR MORE AUTHORS
... (Lui and others 1995).
ANONYMOUS AUTHOR / NO AUTHOR
... (Anonymous 2003).
... (Smith date unknown).
MULTIPLE SOURCES, SAME AUTHOR
Order them chronologically, earliest to latest.
... (Jones 1965, 1973, 1988).
If there are several in the same year, add a designator (a, b, c, etc.) to the year in the citation and the reference list.
... (Jones 1998a, 1998b).
MULTIPLE SOURCES, DIFFERENT AUTHORS
List them chronologically, and alphabetically if they were published in the same year. Separate entries with a semi-colon.
... (Sergeant 1973, 1975; Klevezal and Thompson 1980; Jones 1998a, 1998b; Alberts and others 2001; Stanford 2001).
DIFFERENT AUTHORS, SAME LAST NAME
If the citations would otherwise be identical, provide initials or enough other names to distinguish between them.
... (Smith NB 1993; Smith TR 1993).
... (Elias BL and Elias SR 2004).
... (Smith, Jones, and others 1990; Smith, Williams, and others 1990).
A SPECIFIC PART OF A SOURCE
... (Zelickson and Robbins 1986, p 24).
A SECONDARY SOURCE
Limit your use of this method by obtaining the original paper (e.g., King) whenever possible.
... (King 1911, cited in Brown 2003).
Unpublished information that is not available to other scholars is indicated parenthetically in the text only, with a note indicating it is not in the reference list. Instead, add a "Notes" section at the end of your paper to provide further details about the communication, meeting, or materials, such as purpose, time, date, location, etc.
... (a 1998 Mar 26 e-mail from JR Ewing to me; unreferenced, see "Notes").
... (my 2004 Feb 17 notes from BIOL1030 lecture by T Dukator; unreferenced, see "Notes").
COURSE AND LECTURE MATERIALS
Course readers: Use the article authors as authors and the date on the reader as the year of publication.
... (Winston and Blais 2003).
Course manual: Treat these as books, using the instructor as author (unless another author is indicated).
Lecture notes: Treat these as books if they are published, but as unpublished information if they are your own notes, or are unpublished. Course or lecture notes may be considered "published" only if they have been been copied and distributed in print or on the Web with the instructor's permission.
The reference list comes at the end of your paper and provides the full bibliographic information for your materials. Works you have cited within your paper should be listed in alphabetical order under "References" or "Cited References." If you used other material but didn't specifically cite it, include it in a section called "Additional References."
These examples show you how to format various kinds of reference list entries.
ONE TO TEN AUTHORS
Author AA, Author BB, Author CC. Year. Title of work. Edition. Place of publication: Publisher name. Number of pages p.
Agrios GN. 1978. Plant pathology. 2nd ed. New York: Academic Press. 703 p.
Davidson RH, Lyon WF. 1979. Insect pests of farm, garden, and orchard. 7th ed. New York: John Wiley & Sons. 596 p.
MORE THAN TEN AUTHORS
List the 1st to 10th authors, followed by "and others."
GROUP AS AUTHOR
Provide the abbreviation of the group name in square brackets so you can use it in your in-text citation, but make sure you also spell out the organization's name.
[ISO] International Organization for Standardization. 1979. Statistical methods. Geneva: ISO; (ISO standards handbooks: 3).
ANONYMOUS AUTHOR / NO AUTHOR
[Anonymous]. 2004. Protocol for sterile procedures. Toronto (ON): Association for Microbiological Standards. 35 p.
Smith RA. [Date unknown]. Health problems in the elderly. New York: John Wiley & Sons. 315 p.
AN EDITED BOOK OR COLLECTION
Author AA, Author BB, editors. Year. Title of work. Edition. Place of publication: Publisher name. Number of pages p.
Gilman AG, Rall TW, Nies AS, Taylor P, editors. 1990. The pharmacological basis of therapeutics. 8th ed. New York: Pergamon. 1389 p.
PART OF A EDITED BOOK OR COLLECTION
Author(s) of the part. Year. Title of the part. In: author(s) or editor(s). Title of the book. Place of publication: Publisher name. p Pages of the part.
Kuret JA, Murad F. 1990. Adenohypophyseal hormones and related substances. In: Gilman AG, Rall TW, Nies AS, Taylor P, editors. The pharmacological basis of therapeutics. 8th ed. New York: Pergamon. p 1334-60.
If the author of the part also happens to be the book author or editor, use this format:
Author(s) or editor(s). Year. Title of work. Place of publication: publisher name. Kind of part and its numeration, title; p Pages of the part.
Hebel R, Stromberg MW. 1976. Anatomy of the laboratory rat. Baltimore: Williams & Wilkins. Part C, Digestive system; p 43-54.
Unpublished information that is not available to scholars is not included in the reference list. (See "Unpublished Information" under "In-Text Citations" above.) Only information available to scholars belongs in the reference list.
Darwin C. 1863. [Letters to Sir William Jackson Hooker]. Located at: Archives, Royal Botanic Gardens, Kew, London, England.
A SECONDARY SOURCE
Limit your use of this method by obtaining the original paper whenever possible. When used, include full references for both documents. The reference for the original document should include a closing note (in parentheses) in the reference list indicating the source reference.
Brown AD. 2003. Feed or feedback : agriculture, population dynamics and the state of the planet. Utrecht: International Books. 431p.
King FH. 1911. Farmers of Forty Centuries. Emmaus (PA): Organic Gardening. 379p. (cited in Brown 2003)
COURSE AND LECTURE MATERIALS
Course readers: Treat articles in a course reader as a part of an edited book or collection edited by the instructor of the course.
Course manuals: Treat these as books or nonperiodicals, with the instructor as author (unless another author is indicated).
Stengos T. (2003). ECON*4640 Applied Econometrics course manual. Guelph, ON: University of Guelph.
Lecture notes: Treat these as books or non-periodicals if they are published, but as unpublished information if they are your own notes, or are unpublished. Lecture notes are considered published if they have been copied and distributed in print or on the Web with the instructor's permission.
Stengos T. (2003). ECON*4640 Applied Econometrics course notes. Guelph, ON: University of Guelph.
Stengos T. (2003). ECON*4640 Applied Econometrics course notes. Guelph, ON: University of Guelph; [cited 23 November 2003]. Available from: http://www.uoguelph.ca/econometrics.htm
Author AA, Author BB. Date of publication. Article title. Newspaper title;section designator: page number(column number).
Rensberger B, Specter B. 1989 Aug 7. CFCs may be destroyed by natural process. Washington Post; SectA:2(col5).
ARTICLE IN A PERIODICAL
Author AA, Author BB. Year. Article title. Journal title volume number(issue number): inclusive pages.
Burns L, Thorpe G. 1979. Fears and phobias. Journal of Internal Medical Research 17(2):235-46.
ARTICLE IN AN ONLINE PERIODICAL
Author AA, Author BB. Date of Publication. Article Title [Article Type]. Periodical Title [Content Designator Medium Designator]. Edition. [Date of Update/Revision; Date of Citation];Volume(Issue): Location/Extent. Available from: URL (Language). Notes.
Tong V, Abbott FS, Mbofana S, Walker MJ. 2001. In vitro investigation of hepatic extraction. Journal of Pharmacy & Pharmaceutical Sciences [Internet]. [cited 2001 May 3];4(1):15-23. Available from: http://www.ualberta.ca/~csps/JPPS4(1)/F.Abbott/RSD1070.pdf
If there is no pagination in your online material, estimate how many pages it has:
Ganz PA. 1997 Apr. Menopause and breast cancer. Innovations in Breast Cancer Care [Internet]. [cited 1997 Nov 4];2(3):[about 10 p.]. Available from: http://www.meniscus.com/bcc/Art2_23.html
Author AA, Author BB. Date of Publication. Title [Content Designator Medium Designator]. Edition. Secondary Authors. Place of Publication: Publisher; [Date of Update/Revision; Date of Citation]. Extent. (Series). Available from: URL (Language). Notes.
Lawrence RA. 1997 Oct. A review of the medical benefits and contraindications to breastfeeding in the United States [Internet]. Arlington (VA): National Center for Education in Maternal and Child Health; [cited 2000 Apr 24]. 40 p. Available from: http://www.ncemch.org/pubs/PDFs/breastfeedingTIB.pdf
If the document has no author, use [Anonymous] or the publisher or group as the author:
University of Iowa. Updated 2000 Apr 25. Metcalfe meta directory of Internet health resources [Internet]. Iowa City (IA): University of Iowa, Metcalfe Library for the Health Sciences; [cited 2003 Jun 30]. Available from: http://www.lib.uiowa.edu/metcalfe/md/index.html
Web site name. Date of Publication or Copyright. [Medium Designator]. Place of Publication: Publisher; [Date of Update/Revision; Date of Citation]. Available from: URL (Language). Notes.
Medtext. c1995-2001. Hypertension, Dialysis & Clinical Nephrology [Internet]. Hinsdale (IL): Medtext, Inc.; [cited 2001 Mar 8]. Available from: http://www.medtext.com/hdcn.htm
Email and postings to discussion lists are considered unpublished information, and are often not accepted for inclusion in a reference list. If you do need to include them, use the following format.
Author of Message. Date of Publication. Title of Message [Content Designator Medium Designator]. Message to: Message Recipient. [Date of Citation]. Extent. Available from: URL (Language). Notes.
Stevens J. 2003 Feb 27, 1:18 pm. Methods of electronic referencing [electronic mail on the Internet]. Message to: John Smith. [cited 2003 Mar 28]. [about 5 screens].
For discussion lists:
AAuthor of Message (Author Affi liation). Date of Publication. Title of Message. In: Title of List [Content Designator Medium Designator]. Place of Publication: Publisher; [Date of Citation]. Numeration of Message. Extent. Available from: URL (Language). Notes.
Smith J. 1998 Feb 23, 10:27 am. WebMD. In: MEDLIB-L [discussion list on the Internet]. [Chicago (IL): Medical Library Association]; [cited 1998 Feb 24]. [about 2 p.]. Available from: MEDLIB-L@LISTSERV.ACSU.BUFFALO.EDU Archives available from: http://www.medlib-l.com
SOME GUIDELINES FOR REFERENCING ELECTRONIC SOURCES
Remember to acknowledge electronic sources and to evaluate them critically since much of the material on the Internet is inappropriate for use in an academic paper.
- Is this reference current?
- Has the work been critically evaluated and if so, by whom?
- Who is the publisher or sponsoring organization? Does the work cite sources? For information about how to evaluate a Web site, look at www.lib.uoguelph.ca and follow the link to Library Education.