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Citation Styles

Information on citing/referencing and what citation style to use for your essay or assignment.

Why cite?

Citing authoritative and appropriate sources not only gives more weight to your argument, it also provides evidence that you have read widely and can represent a wide range of views. It is important to follow a formal system of citing or referencing to avoid plagiarism and to ensure that your reader can easily locate the original sources of your citation.

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Which style do I use?

There are several acceptable citation styles that may be used at the University of Otago. This page details the most commonly used styles. If your department has specified a style that is not shown here, please ask at the Library help desk or contact your department.

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Commonly used citation styles


The ACS style is produced by the American Chemical Society (ACS). ACS is a number-based citation system, where a number is allocated to a source in the order in which it is cited in the text (if it is cited again, the same number is used). While its emphasis is on chemistry, the ACS style is applicable to science, engineering, and medical disciplines. ACS style uses abbreviated journal names. Names should be abbreviated according to the Chemical Abstracts Service Source Index (CASSI).

Chemical Abstracts Service Source Index (CASSI)

Style detail | Style examples | Website

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The following links and examples are based on more detailed information in the Publication manual of the American Psychological Association.

APA is the publishing style established by the American Psychological Association. APA style is used in all of the books and journals that the association publishes, and is widely adopted in the social and behavioural sciences.

Citation generator | Style examples | Style detail | Tutorial | Website

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The Chicago Manual of Style presents two different systems:

Chicago A (notes and a bibliography) presents bibliographic information in consecutively numbered notes, which are placed at either the foot of the page (footnotes) or at the end of an essay (endnotes).

Chicago B (in-text citation and a reference list) presents brief citations in the text (usually in parentheses) of the author’s last name and date of publication.

Citation generator | Style examples | Website

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Harvard is an author-date style, with in-text citations and a reference list (in alphabetical order). The Harvard Citation Style is widely used, but with a number of variations. Consistency is important, make sure that you are consistent in your own application of the style.

Cite it right: guide to Harvard referencing style (330K in PDF format) – University of Limerick

Citing & referencing guide: Harvard style (266K in PDF format) – Imperial College London

Citation generator | Style examples

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Legal citation

For legal citation at Otago, use the NZ Law Style Guide (NZLSG). You may also wish to consult the following guides:

  • The Australian Guide to Legal Citation (AGLC) 3rd edition.  You can download the AGLC, AGLC Endnote style and a Guide to using the style.
  • The Oxford Standard Citation of Legal Authorities (OSCOLA).
  • The Canadian Guide to Uniform Legal Citation (CGULC).
  • The Bluebook is another system of citation used for formatting citations in legal writings, including scholarly writing and court documents.

AGLC | AGLC Endnote Style & Guide | Bluebook | CGULC | NZLSG | NZLSG tips | OSCOLA

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The MLA style is produced by the Modern Language Association and features brief parenthetical in-text citations that point to more detailed information in the alphabetical list of Works Cited which is included at the end of the paper. MLA style is widely used in the humanities, especially in writing on language and literature.

Citation Generator | Citing multimedia | Style detail | Style examples | Tutorial | Website

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Vancouver style follows the rules established by the International Committee of Medical Journal Editors which are also known as the Uniform Requirements for Manuscripts Submitted to Biomedical journals. Vancouver is a numbered style, where a number is allocated to a source in the order in which it is cited in the text (if it is cited again, the same number is used). The Vancouver style is commonly used in medical and scientific journals (e.g. by the National Library of Medicine and the American Medical Association) and for the health sciences, with slight style variations between journals (e.g. use of superscript).

Uniform requirements for manuscripts submitted to biomedical journals – ICMJE

Style examples | Tutorial | Website