What is CSE style?
CSE style is the citation and formatting style of the Council of Science Editors, published in The CSE Manual: Scientific Style and Format for Authors, Editors, and Publishers. It is the standard in biology and the life sciences, and is also used in medicine, ecology, environmental science, agriculture, and earth sciences.
The current edition is the 9th edition (2024). It replaced the 8th edition (2014) and changed several reference-list rules, so references made by older tools may now be out of date. See what changed in the 9th edition.
The three citation systems
CSE offers three ways to link the text of your paper to the reference list. The reference entries are almost the same in all three; what changes is the in-text citation, where the year goes, and how the list is ordered.
| System | In-text | Reference list order |
|---|---|---|
| Citation–sequence | Number, e.g. ¹ or (1) | Numbered in the order each source is first cited |
| Citation–name | Number, e.g. ¹ or (1) | Alphabetical by first author, then numbered |
| Name–year | Author and year, e.g. (Fauci and Lane 2020) | Alphabetical by author, then by year; not numbered |
Here is the same journal article in citation–sequence (or citation–name) and in name–year format. Notice that name–year moves the year directly after the authors.
1. Haasnoot M, Lawrence J, Magnan AK. Pathways to coastal retreat. Science. 2021;372(6548):1287–1290. https://doi.org/10.1126/science.abi6594
Haasnoot M, Lawrence J, Magnan AK. 2021. Pathways to coastal retreat. Science. 372(6548):1287–1290. https://doi.org/10.1126/science.abi6594
Which system should you use?
Always follow your instructor’s or journal’s instructions. If you have a choice:
- Name–year is the most common choice for student lab reports and theses in biology. Readers can see who wrote a source without flipping to the list.
- Citation–sequence keeps the text uncluttered and suits papers with many citations. It is the system The CSE Manual uses for its own references.
- Citation–name is less common. It gives numbered citations but an alphabetical list, which makes long reference lists easier to scan.
Our CSE citation generator lets you switch systems at any time and re-sorts and renumbers your whole list automatically.
In-text citations
Citation–sequence and citation–name
Put the reference number in the text as a superscript or in parentheses, placed right after the information it supports. Use the same number every time you cite that source again.
- One source:
…a new pathogen¹.or…a new pathogen (1). - Several sources: separate with commas, no spaces:
¹,⁴,⁹ - Consecutive sources: use an en dash for three or more:
³–⁶
Name–year
Give the author surname(s) and the year in parentheses. The rules depend on the number of authors:
| Authors | In-text citation |
|---|---|
| 1 author | (Liang 2020) |
| 2 authors | (Fauci and Lane 2020) |
| 3 or more authors | (Haasnoot et al 2021) — 9th edition writes “et al” without a period |
| Organization | (ALSG 2020) — use an abbreviation if you give one in the reference |
| No author | (Health equity . . . 2020) — first word or two of the title |
| Same author, same year | (Lee et al 2020a, 2020b) |
| Several sources | (Fauci and Lane 2020; Haasnoot et al 2021) — order chronologically |
When the author is part of your sentence, put only the year in parentheses: “Fauci and Lane (2020) argue that…”. Use our in-text citation generator to combine several sources correctly.
Building the reference list
Title the list References (or follow your instructor’s heading, such as “Literature Cited”) and start it on a new page at the end of your paper.
- Citation–sequence: number references in the order they are first cited.
- Citation–name: alphabetize by first author’s surname, then number. Two works by the same author are ordered by title.
- Name–year: alphabetize by author, then by year. Same author and same year: add “a”, “b” to the year.
- A hanging indent is not required but makes the list easier to read.
- Every reference must be cited in the text, and every in-text citation must appear in the list. Personal communications are cited in the text only.
Authors
Write each author as surname followed by initials, with no periods or spaces between initials: Magnan AK, not Magnan, A. K.. Separate authors with commas.
- 1–5 authors: list them all.
- 6 or more authors: list the first author followed by “et al”. The 8th edition listed up to 10.
- Hyphenated given names keep the hyphen: Jean-Paul Martin →
Martin J-P. - Suffixes follow the initials without a comma:
Corrigan TJ Jr. - Organizations are written in full. In name–year, you can add an abbreviation in brackets to shorten in-text citations:
[ALSG] Advanced Life Support Group. - No author? Start the reference with the title.
Ashraf M et al. Interaction between the distribution of diabetic retinopathy lesions and the association of optical coherence tomography angiography scans with diabetic retinopathy severity. JAMA Ophthalmol. 2020;138(12):1291–1297. https://doi.org/10.1001/jamaophthalmol.2020.4516
Titles and capitalization
CSE uses sentence case for article, chapter, and book titles: capitalize only the first word, proper nouns, and acronyms. The word after a colon is lowercase. Titles are not italicized, underlined, or put in quotation marks.
De Doncker RW, Duco WJP, Veltman A. Advanced electrical drives: analysis, modeling, control. Springer; 2020.
The exception is scientific names: genus and species names are always italicized, as in Escherichia coli or E. coli. Our sentence-case converter handles both.
Journal abbreviations
CSE abbreviates journal titles using the ISO 4 standard (the ISSN List of Title Word Abbreviations), written without periods:
| Full title | CSE abbreviation |
|---|---|
| Journal of Food Science | J Food Sci |
| New England Journal of Medicine | N Engl J Med |
| Proceedings of the National Academy of Sciences of the United States of America | Proc Natl Acad Sci U S A |
| Science | Science (one word, not abbreviated) |
Look up official abbreviations with our journal abbreviation finder, which searches the NLM Catalog.
Dates, pages, and DOIs
- Dates are written year–month–day with three-letter months and no punctuation:
2021 Apr 9. Journal articles and books usually need only the year. - Page ranges are given in full with an en dash:
1287–1290, not1287–90. Online-only articles use the article number. - Volume and issue run together with no spaces:
2021;372(6548):1287–1290. - DOIs are written as full links at the end of the reference, with no period after them:
https://doi.org/10.1126/science.abi6594. - Websites: give the date published and any update date:
2020 Apr 30 [updated 2022 Jan 25]. In the 9th edition, add[accessed …]only if there is no date.
Health equity considerations and racial and ethnic minority groups. US Centers for Disease Control and Prevention, National Center for Immunization and Respiratory Diseases, Division of Viral Diseases; 2020 Apr 30 [updated 2022 Jan 25]. https://www.cdc.gov/coronavirus/2019-ncov/community/health-equity/race-ethnicity.html
Common mistakes
- Using Title Case or italics for article and book titles.
- Putting periods in initials (
Smith J.A.) or in journal abbreviations (J. Food Sci.). - Listing all authors of a 20-author paper — the 9th edition stops at 5.
- Writing DOIs as
doi:10.…(8th edition style) instead of a https://doi.org link. - Including the city of publication for books (no longer used in the 9th edition).
- Shortened page ranges like
123–9. - Forgetting to italicize species names.
- Mixing systems, e.g. numbered in-text citations with an alphabetical, unnumbered list.
Our generator avoids all of these automatically and warns you about missing information.
Frequently asked questions
What is CSE citation style?
CSE style is the referencing system set out by the Council of Science Editors in The CSE Manual: Scientific Style and Format for Authors, Editors, and Publishers. It is used widely in biology, life sciences, medicine and environmental science. The current edition is the 9th edition, published in 2024.
Which CSE system should I use: citation–sequence, citation–name, or name–year?
Use whichever your instructor or journal specifies. Citation–sequence numbers references in the order you first cite them. Citation–name sorts the list alphabetically and then numbers it. Name–year puts the author surname and year in the text, e.g. (Fauci and Lane 2020). If you have no instructions, name–year is the most common choice for student papers in biology.
Is this generator updated for the CSE 9th edition?
Yes. By default it follows the 9th edition (2024): up to five authors are listed before "et al", DOIs are written as https://doi.org/ links, publisher locations are omitted, and access dates are only included when a web source has no date. You can switch to the 8th edition (2014) if your instructor still requires it.
How do I cite a source with more than five authors in CSE?
In the 9th edition, list the first author followed by "et al" (e.g. "Ashraf M et al."). If there are five or fewer authors, list them all. In name–year in-text citations, use "et al" for three or more authors, e.g. (Haasnoot et al 2021). The 8th edition listed up to ten authors.
Should journal names be abbreviated in CSE?
Yes. CSE uses the ISO 4 abbreviation of the journal title, without periods, e.g. "J Food Sci" for Journal of Food Science. One-word titles such as Science or Nature are not abbreviated. Lookups by DOI or PubMed ID fill in the official abbreviation automatically, and our Journal Abbreviation Finder searches the NLM Catalog.
Are titles italicized in CSE?
No. Article, book and journal titles are not italicized or put in quotation marks, and titles use sentence case (only the first word and proper nouns are capitalized). Scientific names of genera and species, such as Escherichia coli, are italicized wherever they appear.
Can I cite a PDF?
Yes. Choose “Cite a PDF” or drop the file onto the generator. It finds the DOI, arXiv ID, PubMed ID, or ISBN inside the PDF and builds the reference from the official record. If there is no identifier, it matches the title against Crossref or fills in what it can for you to finish. The PDF is read in your browser and never uploaded. You can also import several PDFs at once with Import, below your bibliography.
Does my bibliography get saved?
Your references are saved in your browser on this device, with no account. You can keep several lists, and export them to Word, PDF, plain text, RIS, BibTeX, or CSL-JSON at any time. Clearing your browser data removes them, so export anything you want to keep.
Is the CSE Citation Generator free?
Yes. It is completely free, with no sign-up, no ads, and no paywalled features.
This guide summarizes rules in The CSE Manual, 9th edition (Council of Science Editors, 2024). For full details and edge cases, consult the manual or the CSE Citation Quick Guide.