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Biology Research

List of resources in Biological Sciences for Undergraduate Biology Majors.

The Council of Science Editors (CSE) allows authors three systems of documentation. In all three systems, a reference list at the end of the paper provides all the information a reader needs to track down  sources. 
In-text references in sentences show a reader which sources support the claims and information of that sentence.

This guide contains step-by-step instructions for properly applying CSE style.

Content adapted from University of Wisconsin Writers' Handbook, CC BY SA


The Council of Science Editors (CSE) style is designed for the general sciences including biology. You need to cite your sources in two places within your paper: in-text and bibliography

There are three types of in-text citation options for the CSE:
❖ Name-Year,

In-text references consist of paraphrased descriptions of research done by others. In the Name-Year style, parentheses are placed around the author's surname and year of publication. 

Quotes are rarely used in scientific publications.

What are In-Text References?

 In-text references consist of paraphrased descriptions of research done by others.

In the CSE citation systems described here, numbers in a sentence refer to sources listed at the end of the document. Two of these systems, (citation-sequence, citation-name), differ only in how sources are numbered in the reference list: sequentially (citation-sequence) or alphabetically by author's name,(citation-name).

A third system, Name-Year, is used in some contexts. In this style, following a sentence in which the concepts derive from another's work, the authors surname and year of the publication from which the ideas derive appear in parentheses.

Step One: Which System?

When choosing which citation system to use consider the following:

  • In the citation-sequence system, sources are numbered by order of reference, so that the first reference cited in the paper is 1, the second 2, and so on.
  • In citation-name, the sources are numbered alphabetically so that 1 refers to the first source in an alphabetical list, 2 refers to the second source in that list, and so on.

When possible, put numbers immediately after the relevant word or phrase rather than at the end of a sentence.

  • In Name-Year, references in your text give the last name of the author or authors and the year of publication within parentheses. These parenthetical refer to sources listed at the end of the document.

The use of any of the three CSE citation styles may be dictated by the context in which a researcher finds herself. However when choosing which to follow bear in mind that it is in the Reference List that the importance of your system resides. The goal is for a reader easily to connect a number in the text with its source in the reference list at the end of the paper. Whether this is most easily accomplished by alphabetically listing the references to begin with and then assigning a number to each, or by numbering the citations in the text as you go along and then correlating them to the sources in the Reference List at the end is for each author to decide.

Step Two: Format in-text references

  • In the style advocated by CSE  numbers appear in superscript, and appear before punctuation marks (commas or periods).

Example from The CSE Manual:

Traumatic life events and post traumatic stress disorder (PTSD) are endemic among American civilians 1.

However, many scientific journals format these numbers differently, using square brackets or parentheses, or putting superscript numbers after the period.

The most fundamental specialization of the eusocial insects is the division of colony members into two castes, workers (functionally sterile individuals) and reproductives.1

The classical cadherin system connects cadherins to the actin cytoskeleton via b-catenin and a-catenin to maintain tissue integrity in metazoans [1].

Although xylem is considered a nutrient-limiting, low-oxygen environment (1), R. solanacearum is well adapted to it, growing to cell densities of 108 to 109 CFU/g stem while still remaining limited to xylem (2).


The Reference List

What is the Reference List?

"Reference list" is CSE's generic term for the list of sources at the end of your document. Your list should be given a more formal title: References or Cited References, Literature Cited, or Bibliography. It alphabetically lists and matches the sources cited within the text, including tables and figures.

If you used some documents as sources but did not cite them in your paper, list them alphabetically by author under the heading Additional References.

The Reference List exists to help your reader identify each numbered source quickly and clearly. CSE has standardized the information to be provided for ease and predictability of reading.

How to Format the Reference List

  • Authors' first names are rendered as capitals after their surnames.

          Otegui MS, Kiessling LL, Batzli J.

  • Only the first word of a book or article title should be capitalized.

           The fat-soluble vitamins: handbook of lipid research 2.

  • Titles are not italicized. However, species names are italicized.

            In vitro and in vivo reconstitution of the cadherin-catenin-actin complex from Caenorhabditis elegans.             Proc Natl Acad Sci. 2010 Aug 17;107(33):14591-6.

  • To save space, journal titles are abbreviated according to the ISO 4 standard, shortening significant words and omitting insignificant words. Read more and search the List of Title Word Abbreviations at

         Livestock Prod Sci. 
         Biochem Mol Biol Educ. 
         J Dairy Sci.

  • Year of publication and volume number are required for all references to articles. Issue number is strongly recommended. To save space, use no spaces to separate an article's date, volume, and page.

         Annu Rev Phytopathol. 2012;50:425-49. 
         Mol Plant Microbe Interact. 2011 Jul;24(7):773-86.