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Citation Styles for the Sciences

In-Text Citations

In the name-year system, in-text references contain the name of the author(s) and the year of publication, enclosed in parentheses. Leave a space between the authors' names and the year. There should be no comma between the last author's name and the year.

One Author

(Name year of publication).

(Smith 2009)

If the author's name is stated in the sentence, only the year is needed.

Smith's (2009) study shows that...

Two Authors

(Author and Author year)

(Flannigan and Sims 2003)

If the surnames are identical, add the initials.

(Smith TL and Smith UT 1999)

Three or More Authors

(First Author et al. year)

(Dawson et al. 1986)

Organizations as Authors

If an organizational author is only referenced once or twice in a document, use the full organizational name.

(Organization year)

(National Library of Medicine 2002)

A shortened form of the organization's name can be used if it has a familiar abbreviation

(NSF 2005)

If an organizational author is referenced several times in a document, a shortened form of the organizational name can be used. In this case, use the initial letter of each part of the name or a recognizable abbreviation. Include the abbreviation as the initial element of the end reference within square brackets.

(NLM 2004)

End reference: [NLM] National Library of Medicine (US). 2004.



Author(s). Date. Title. Edition. Place of publication: publisher. Extent. Notes.


Schott J, Priest J. 2002. Leading antenatal classes: a practical guide. 2nd ed. Boston (MA): Books for Midwives.

Conference Papers

Author(s) of paper. Date. Title of paper. In: Editor(s). Title of book. Number and name of conference; date of conference; place of conference. Place of publication: publisher. Location. Notes.


Lee DJ, Bates D, Dromey C, Xu X, Antani S. c2003. An imagining system correlating lip shapes with tongue contact patterns for speech pathology research. In: Krol M, Mitra S, Lee DJ, editors. CBMS 2003. Proceedings of the 16th IEEE Symptosium on Computer-Based Medical Systems; New York. Los Alamitos (CA): IEEE Computer Society. p. 307-313.

Conference Proceedings

Editor(s). Date. Title of book. Number and name of conference; date of conference; place of conference. Place of publication: publisher. Extent. Notes.


Antonioli GE, editor. c1997. Pacemaker leads 1997. Proceedings of the 3rd International Symposium on Pacemaker Leads; 1997 Sep 11-13; Ferrara, Italy. Bologna (Italy): Monducci Editore.

Dissertations and Theses

Author(s). Date. Title of dissertation and thesis [content designator]. Place of publication; publisher. Extent. Notes.


Lutz M. 1989. 1903: American nervousness and the economy of cultural change [dissertation]. [Stanford (CA)]: Stanford University.


Author(s). Date of publication. title of book. Edition. Place of publication: publisher; [date updated; date accessed]. Notes.


Griffiths AJF, Miller JH, Suzuki DT, Lewontin RC, Gelbart WM. c2000. Introduction to genetic analysis. 7th ed. New York (NY): W. H. Freeman & Co.; [accessed 2005 May 31]. TOC.

Journal Articles (Online)

Author(s). Date of publication. Title of article. Title of journal (edition). [date updated; date accessed];Volume(issue):location. Notes.


Savage E, Ramsay M, White J, Beard S, Lawson H, Hunjan R, Brown D. 2005. Mumps outbreaks across England and Wales in 2004: observational study. BJM. [accessed 2005 May 31];330(7500):1119-1120. doi:10.1136/bmj.330.7500.1119.

Journal Articles (Print)

Author(s). Date. Article title. Volume(issue):page numbers.


Smart N, Fang ZY, Marwick TH. 2003. A practical guide to exercise training for heart failure patients. J Card Fail. 9(1):49-58.

Journal Articles With More Than 10 Authors (Print)

First 10 authors' names, et al. Date. Article title. Abbreviated journal title. Volume(issue):page numbers.


Pizzi C, Caraglia M, Cianciulli M, Fabbrocini A, Libroia A, Matano E, Contegiacomo A, Del Prete S, Abbruzzese A, Martignetti A, et al. 2002. Low-dose recombinant IL-2 induces psychological changes: monitoring by Minnesota Multiphasic Personality Inventory (MMPI). Anticancer Res. 2002;22(2A):727-732.

Technical Reports

Author(s). Date. Title of report. Edition. Place of publication: Publisher. Extent. Report No.: Notes.


Feller BA. 1981. Health characteristics of persons with chronic activity limitations, United States, 1979. Hyattsville (MD): National Center for Health Statistics (US). Report No.: VHS-SER-10/137. Available from: NTIS, Springfield, VA; PB88-228622.


Title of homepage. Date of publication. Edition. Place of publication: publisher; [date updated; date accessed]. Notes.


APSnet: plant pathology online. c1994-2005. St Paul (MN): American Phytopathological Association; [accessed 2005 Jun 20].