BIO 190—Scientific Communication I

Bibliographic citation

A basic item of information in the biological literature is the bibliographic citation. A bibliographic citation is designed to be a unique identifier for a “piece” of literature: an article, a book, a web page, whatever. You have already seen many bibliographic citations, especially in bibliographies (which consist of nothing more, unless they are “annotated bibliographies”) and on library catalog computers.

To understand bibliographic citations, it is important to focus on the two words “unique” and “identifier”. A single citation should correspond to only a single piece of the literature, and it should permit the retrieval of that piece of literature.

Bibliographic citations come in many different formats, some of them similar and others different enough that they at first don’t look like citations. But every one of them has four basic pieces of information:

  1. Author
  2. Year of Publication
  3. Title
  4. Source

The first step in making a bibliographic citation is to find those four pieces of information. The second step is to make sure there is enough information to uniquely identify the literature. The third step is to format it appropriately.

Finding the information

  • Some notes about authors
    • Single author - This is virtually self-explanatory. It is important, however, to record the complete name of the author from the publication. For example, if the publication says “Charles Robert Darwin”, and you are used to a citation style that would require “Darwin, C. R.”, you might be tempted to write down just the initials. But if at a later date you needed to use a different citation style that required full names, you’d either have to look up the reference again or try to remember Darwin’s middle name. Also, pay attention to accented characters and other diacriticals (many of you have heard of the physicist Angstrom, whether or not you know his name was actually spelled Ångström, but you may face a citation style someday where the accents are important).
    • Multiple authors - The order of multiple authors is significant, and it is determined by formal and informal rules and practices that are often confusing. For bibliographic citation, the important rule is preserve the order of multiple authors. There is never a reason to change it. If you are faced with 34 different authors on a publication, write them all down. The phrase “et al.” (from the Latin et alii, “and others”) is acceptable when citing a reference in text (for example, Clark et al., 1998), but many citation styles require every author, and the thing you want to avoid in this business is going back to the library to look at the same reference again, because you forgot to write something down. Complete lists of multiple authors are one of the ways of uniquely identifying a publication.
    • “Corporate” authors - Corporate in this sense means an author that is a group or organization rather than a person. Who is the author of the Cal Poly course catalog? No single individual or group of individuals takes credit for it, so its author is “California State Polytechnic University, Pomona”. Always look carefully for actual people who are authors before deciding that a publication has a corporate author.
    • Editors - For publications that are collections of smaller works by individual authors, the name of the editor takes the place of the author’s name. Be sure to note when someone is an editor rather than an author, because virtually every citation style makes a distinction.
    • No author - If a publication has no author, record the author as “Anonymous”. Some citation styles use that word, and others leave off the author altogether.
  • Books: When it comes to bibliographic citation, the two most important pages of most books are the title page, and the other side, or reverse, of the title page. You might be tempted to get information from the cover or spine, but they are no more accurate, and sometimes less accurate, than the title page and its reverse.
    1. Author (title page) - Copy the names of the authors exactly as they appear, but omit honorifics such as “Ph.D.” or “Fellow of the Royal College of Surgeons”, and affiliations (their universities, for example). If a book has a corporate author, it will often be on the title page in the same position as a human author.
    2. Year of Publication (reverse of title page) - For a book, the year of publication is almost always the most recent copyright date. The only exception is when there is a more recent date assigned to an additional printing, e.g. “sixth printing 1989”. If there is more than one copyright date (© 1972, 1984, 1993), these usually refer to different editions of a book. Always use the most recent. (Note also that the holder of copyright is not part of the bibliographic citation, although it is often the same as the publisher or author.)
    3. Title (title page) - Copy exactly as it appears. If there is a subtitle, connect it to the title with a colon, e.g. “The Units of Evolution: Essays on the Nature of Species”. In general, don’t worry about capitalization, since it is usually specified by the citation style. But pay attention to words that are capitalized or italicized for reasons other that ordinary rules of style, and copy them exactly: Mus musculus, rbcL, nrDNA.
    4. Source (either title page or reverse) - For a book, the source consists of the name of publisher, followed by the location of the publisher. This information is usually on the title page, and if it is, you should obtain it there, but if parts are missing, you can look for them on the reverse. Sometimes there is more information than you need:

          A Bradford Book
          The MIT Press
          Cambridge, Massachusetts
          London, England

      The citation would be “MIT Press, Cambridge, MA”. These often require some guesswork. The state or country should be included when it is not obvious: “London” [England], but “London, Ontario, Canada”, “Moscow” [Russia], but “Moscow, Idaho”.

    5. Number of pages - This item does not exactly fit any of the four parts of a citation, but some styles require it (it is another way of making a citation unique), so you should always record it. Look at the end of the book for the last page that has a printed number, and write that number down.

    Warning - On the reverse of the title page many books have something called “Library of Congress Cataloguing-in-Publication Data”. It looks vaguely like an entry in a library catalogue, and it is a bibliographic citation. It is not necessarily complete, however, and you should avoid using it unless you can’t find the information elsewhere.

  • Books with articles: In biology, many books contain chapters written by different authors, with the entire book having an editor. If you wanted to cite the entire book, you would do so as above, with the exception of “ed.” after the editor’s name, to indicate that she isn’t an author. But if you wanted to cite an individual chapter or article, it is more like citing a journal article.
    1. Author - Each chapter or article will have the author or authors listed usually on its first page. Sometimes the editor of the book will also author a chapter - don’t be confused by this.
    2. Year of Publication - The year of publication of an article is the same as the year of publication of the book
    3. Title - The title of the article or chapter is generally found on its first page.
    4. Source - The source for an article or chapter is the full bibliographic citation of the book that contains it. Here is an example listed out as expected in the early assignments:

      1. Author: Peter H. Raven
      2. Year: 1977
      3. Title: The California Flora
      4. Source: Chapter 4 (pp. 109-137) in:
        1. Editor: Michael G. Barbour and Jack Major
        2. Year: 1977 [this really doesn’t need to be repeated]
        3. Title: Terrestrial Vegetation of California
        4. Source: John Wiley & Sons, New York. 1002 pp.

      The same citation in the bibliographic style of this class:
      Raven, Peter H. 1977. The California flora. pp. 109-137 in Barbour, Michael G., and Jack Major, eds., Terrestrial Vegetation of California. John Wiley & Sons, New York. 1002 pp.

      Here are scans of the title page, reverse of the title page, and first page of the article so that you can see how the citation is developed.

  • Periodicals: Periodicals (in fact, most serials) are issued in sequentially numbered volumes. These most often correspond to years, but some journals have volumes that span several years, and others, such as Science, have several volumes a year. Individual journals (the items you hold in your hand, as they are shipped from the publisher) are called issues; each issue has an issue number, which gives rise to the alternate name for issues, numbers. If you were looking at volume 12 of a journal issued four times a year, you would likely see Vol. 12, No. 1; Vol. 12, No. 2; Vol. 12, No. 3; and Vol. 12, No. 4. Some journals (again, Science is an example) do not reset the issue number at the beginning of each volume.

    Many periodicals have “cumulative pagination”: No. 1 might consist of pages 1-114, No. 2 would be 115-226, No. 3 would hold pages 227-318, and No. 4 pages 319-442. If you look at any issue of a journal other than a No. 1 and its first page is “1”, it doesn’t have cumulative pagination. If it isn’t, it does.

    Ordinarily you will be citing articles in a periodical, not the periodical itself. Some modern periodicals have all the bibliographic information on the first page of each article. The title and author are normally there, and the remainder of the information is in a header or footer.

    1. Author - This is the author or authors of the individual article, not the editor of the journal. Copy down all authors, exactly as they appear, but again leave off honorifics and affiliations.
    2. Year of Publication - This is always the volume year. If you look at the front of a journal, you might see something like:
      Volume 47 March 1998 Number 1
      The year of publication is 1998. The volume year is almost always the same as the copyright year, but if an issue is delayed, it occasionally is copyright the next year. If you were to use the copyright year, there would no longer be a correspondence in these cases between volume and year, which would cause confusion.
    3. Title - The title is ordinarily at the top of the first page of the article, and also in the table of contents. You should use the one on the article, unless the one in the table of contents seems more complete or correct. Subtitles are handled just as in books.
    4. Source - The source of a journal article is the name of the journal, the volume number, the issue number, and the first and last pages of the article (the pagination).
      • Name of the journal: Here is a place where you want to avoid subtitles. The cover of the journal may say “Systematic Biology: A Quarterly of the Society of Systematic Biologists”, but the name of the journal is Systematic Biology. In many areas of biology, there are standardized lists of journal names, in some cases with standardized abbreviations (botanists, for example, use Botanico-Periodicum Huntianum, which, despite its Latin title, is written in English). A reference librarian can tell you about such guides for other disciplines. If there isn’t a guide, or you haven’t referred to it, copy down the journal name unabbreviated.

        Sometimes journals change their names. For example, Proceedings of the American Academy of Arts and Sciences is now Daedalus. This doesn’t affect the citation - you use the title that was in effect when the article was written - but it can be confusing when you are looking for references.

      • Volume number: This is usually obvious, but especially if you are working with older references, you may see references to such things as “new series” or “n.s.” For various reasons, some journals in the past decided to start their volume numbering over again. You may need help from a librarian if you have a reference like this, which is why librarians convinced most journal publishers to stop the practice.
      • Issue number: You’ll see references in bibliographies that lack issue numbers: “Amer. J. Bot 36: 237-243” rather than “Amer. J. Bot 36(2): 237-243”. This is permissible because the journal in question has cumulative pagination. Page 237 happens to be in issue number 2, and only in issue number 2, so the issue number isn’t essential. But if a journal lacks cumulative pagination, the issue number is crucial, since page 1 could be the first page of any issue. It is always a good idea to write down the issue number, even if you know the journal has cumulative pagination. You might face a citation style someday that requires it, and in these days of unbound issues in the library, it will make it easier for you if you need to go back to that issue.
      • Pagination: This consists of the numbers of the first and last pages of the article.
  • Web pages: Web pages are by far the most difficult subjects for citation, because (a) most people who make web pages don’t have a clue about the need for bibliographic citation, (b) even the people who have a clue often don’t pay as much attention as they should, and (c) web search engines often take you to an individual page of a larger work.

    There’s not much you can do about the first two problems, but there is a lot you have to do about the last. Think of this analogy: You do a search with a standard bibliographic tool like the Wilson Index, and instead of giving you the citation of an article, it gives you the text of a single page of a journal. You see the topic you wanted right there in the middle of the page, but you don’t have any idea where that page belongs, and no way to cite it.

    Web search engines can leave you in exactly the same predicament, except that the Web provides the tools to get out of it. If you are not yet familiar with URLs (Uniform Resource Locators), which are the addresses of web pages, read the Introduction. What you’ll be doing is carving pieces off a URL, starting at the right, and looking to see what you get. Let’s use the URL for this page as an example. Ordinarily you would edit the URL in the “Location:” or “Address:” box in your web browser, but I’ve set up the example URLS below so that you can click on them to see where they would go. Just use the “back” button on your browser to get back to this page. /~jcclark/classes/bio190/bibcit.html
    This URL takes you to this page. Because I took the time to do so, this page (and all the rest in this course) has a bibliographic citation at the bottom. It also has a link taking you back to the main BIO 190 home page, and if you were to click it, you could see the context of this page in the entire course. But let’s say you are looking at a page that lacks both of these, and there is no indication of its author or source. Carve off the file name. /~jcclark/classes/bio190/
    In this case, removing the file name gives the index file (called index.html on this system) of the directory that contains this page. Sure enough, it is the main BIO 190 page. But if that weren’t enough, you could remove the directory name bio190/. /~jcclark/classes/
    That would give you a directory listing of the classes/ directory. You see this listing because classes/ doesn’t have a file called index.html. You can click on any of the listed files to see its contents. If you were still having problems, you could remove the directory classes/. /~jcclark/
    Now you are looking at the index.html file of my main user directory (that’s what the “~” symbol means) - it is my “home page”. Any time you see a user directory as part of a URL, and it has a home page, you can reasonably assume that person is responsible for the contents of all the directories included in it. As a last step, let’s take off the user directory. /
    This is the primary index file of the computer “ ”, and it’s the Cal Poly Pomona home page. For university sites, this provides information, but just because a personal web page is on GeoCities, or Earthlink, or even the Cal Poly Pomona Intranet, that doesn’t mean that the owner of the computer is the publisher.

    1. Author - Use the “carving” technique above to look for a person responsible for the page of interest. Web pages sometimes have corporate authors, and “Anonymous” is always an option, but don’t assume a page is anonymous until you’ve tried to find the author.
    2. Year of Publication - The first choice is the year associated with a “last revised” or “last updated” statement. Second is a copyright year. Third is the file creation or last modified date, but you have to be somewhat of a geek to figure that out (in Netscape 4, View | Page info, and in Internet Explorer, File | Properties, sometimes gives those dates). As a last resort, put the year in which you looked at it (in the citation style for this class, such a year is put in square brackets: [1998]).
    3. Title - There are two places you might find a title on a web page. One part is called the “title”, and it is what appears in the bar at the top of the browser window. This is the title that appears in search engines. The other is in the form of large or emphasized text at the top of the actual page, the place where you would ordinarily look for a title. Ideally these would be the same, or at least very similar (pick the more informative if they differ). Unfortunately, people who make web pages often don’t attend to the title bar “title”, and you might even see “Untitled Document” or some such that was put in by the web page program and never changed. The worst situation couples that with a page that starts out with paragraph text. In that case you could put “Untitled” for the title in your citation, but you have to ask yourself whether such a page would contain anything of value.
    4. Source - As an absolute minimum, the source must include the full URL; otherwise the entire citation is worthless. Be aware that Web browsers (especially Netscape) often abbreviate the URL on printouts of web pages if it is long, so that, for example, this page might look like “http://www.csupomo....s/bio190/bibcit.html”. Make sure you have the full URL before you leave a page, so you don’t have to go back.

      It is important not to stop with the URL. Is there an organization that could be considered the publisher? Again, it takes some detective work, but it results in a better citation.

Citation: Clark, Curtis. 2001. BIO 190 - Bibliographic citation. California State Polytechnic University, Pomona, /~jcclark/classes/bio190/bibcit.html.


These are official class materials of BIO 190 as taught at California State Polytechnic University, Pomona, by Curtis Clark. They are subject to change without notice to anyone but students currently enrolled in the class.

Summer Quarter, 2001
© 2001 by Curtis Clark