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CSE Manual for Scientific Style and Format

How to document scientific writing using the CSE Manual

Name and Year (N-Y) System or Harvard system:

 In Name and Year (N-Y) System, each citation in text is designated by the last name(s) of the author(s) followed by the year of publication of the document.  The name and the date are enclosed within parentheses.  The citations are arranged in the "References" section by the alphabetic order of the last name of first author of the document that you are citing.               

ExampleFor instance, siblings or maternal half siblings born in different breeding seasons might learn to recognize each other as a result of association with their common parent or parents (Sherman 1980).

Name and Year Citation Examples

To accommodate  the in-text citations of multiple works published by the same author, authors with identical last names, multiple authors, corporations and organizations as authors, works with ”unidentifiable authorship” and works with multiple dates, the N-Y format needs to be modified. Following are the examples.


Documents Published by the Same Author in Different Years

Documents published by the same author in different years should be cited in chronologic order.

  •  Example:  Studies of congenic mice, however, reveal an interesting relationship between alleles and discrimination abilities (Yamazaki et al., 1976, 1980).

Same author in the same year

To refer to more than one work by the same author published in the same year, use alphabetic designators (e.g. a,b,c) with the year.

  • ExampleConsiderable information has been gathered about the behavioral ecology of this social sciurid (Sherman 1977, 1980, 1981a, 1981b), allowing us to pursue both "proximate" and "ultimate" questions.

Authors with Identical last names

If you cite the works of two authors who have identical last names and their works published in the same year, include the authors’ last name and initials both in-text references with the years  and separate them by a semicolon and a space.

  •  ExamplePrevious studies (Fernandez I 2002; Fernandez J 2002) investigated the helical secondary structure of a multifunctional membrane protein.

Citation of a work with authors

If a cited work has two authors, mention both last names, separated by "and".

  • Example:  Recombinant Adenoviruses (rAd) comprise one of the major classes of vectors being evaluated for human gene therapy (Roth and Cristiano 1997).

If both authors have the same last name, use their initials in the in-text citation.

  • Example:  Glioblastoma response to radiation was previously studied (Smith R and Smith KA  2010).

Three or more author citations

Documents with three or more authors are cited by the last name of first author followed by "and others" or "et al" and the publication year. Do not use a comma before et al.; always use a period after al.

  •  ExampleThe growth retardation of Tao-Yuan swine has been associated with lower levels of growth hormone in the peripheral circulation (Cheng et al. 1998). 

Corporations or Organizations as author

Corporate or organizational names cited as authors should be given in an abbreviated form or acronym. Use the initial letter of each part of the name or a readily recognizable abbreviation to create a shortened form for the in-text reference. This shortened form, within square brackets, becomes the initial element in the reference.

  • Example:  Conventional tag and release data demonstrate that all size classes of Bluefin have the propensity to make trans-Atlantic crossings (NRC 1994).

Unidentifiable author

If the author is not known or cannot be identified, do not use "anonymous". Cite the document in the text using the first or first few words of the title, followed by an ellipsis.

  • Example:  The benefits of ethanol as an alternate source of energy have already been studied (Ethanol overview………2011).

In-text reference of multiple works by the same author

When you cite multiple works of an author whose name is a part of a sentence, place the year in parentheses in chronological order, if you follow N-Y system.

  • Example: Berridge’s studies on Dopamine (1998, 2007, 2009) showed……….

Multiple citations at 1 point

 When two or more documents are cited together in parentheses, they should be cited in a chronological order from earliest to latest.  Those published in the same year should be sequenced alphabetically by author’s name.

  • Example:  Studies have generally indicated a back and forth movement of fish with tidal cycles and a relatively slow movement through the transition zone (Stasko 1975;  Potter 1988;  Priede et al. 1988;  Soloman and Potter 1988).

Works with no dates

Sometimes with older publications or manuscripts as well as some web publications, it is not possible to find any dates associated with the documents. For in-text references, these publications with no dates should be mentioned with the words “date unknown” within square brackets.

  • Example: The American Chemical Society was established in 1876 ( ACS [date unknown]).