Check your references

When you need this page: Optional

Paste or drop your references.bib, and optionally your preamble.tex and chapters; the page lists common problems (repeated keys, missing fields, names, dates) and the fix for each. Then compile and look at the reference list in your PDF.

Nothing is uploaded. The page reads your files in your browser and saves nothing.

The check needs JavaScript, which is off or not available in this browser. Use the checklist below with your .bib file and PDF.

Read the results

Results are grouped by how they may affect your references:

• May stop citations: repeated keys, missing cited entries, or broken entry syntax. These can cause errors or unresolved citations in the PDF.
• May print wrong: missing usual fields, access dates, or a name that may be parsed incorrectly. Check the source before adding information.
• Style advice: fields worth adding, possible capitalization problems, and settings that may hide fields. Advice can be wrong for a particular source or a customized style.
• Tidy-ups: possible duplicate records, repeated DOI links, or entries not cited in the supplied chapters, if you requested that check.

Every point gives the key (the label after @book{, for example), the field, and its line in the box (with the file name when you added several .bib files). Choose the line to select that entry or field in the box. Each point also suggests a fix and links to the guide section that explains it. By entry lists the same points under each entry instead.

Safe fixes

A few points have a fix the page can make for you. Each one shows the field now and after the fix; nothing changes until you choose the button, one fix at a time or all at once. The page offers a fix only when the change is certain and keeps the meaning:

• escaping a literal &, %, _, or # in a text field (not in names, links, or math);
• keeping only the DOI when doi holds a full https://doi.org/ address or starts with doi:;
• writing an English month name, such as January, as its number;
• moving a full date such as 2020-05-01 from year to date;
• adding a missing comma between two fields.

Fixes never add information, such as dates, DOIs, or pages, and never change keys; everything else stays advice for you to check against the source. The fixes change only the text in the box. Choose Download to save the corrected file, and use it in place of your old one. Undo the fixes restores the text from before them. If Zotero exported the file, correct the record in Zotero as well and export again, or the next export replaces your changes; see auto-export cautions.

Checklist without JavaScript

• Each key is unique, including capitalization; every cited key exists in a .bib file your document loads.
• Each entry has its usual fields: an article's author, title, journal, and date; a book's author or editor, title, date, and publisher; a chapter's book title and pages; a thesis or report's institution and type. Compare with the source and your style guide.
• Each URL has urldate = {YYYY-MM-DD}, the date you read it, and that access date appears in the PDF. This follows the OGE manual §3.4 p. 34 (access dates). DOIs alone do not need access dates.
• Publication dates use date = {YYYY-MM-DD} (or a year or year-month when that is all the source gives). A separate year is four digits; month is a number or a month macro such as jan.
• doi contains the identifier, such as 10.1234/example, rather than a full web address. Check DOI and ISBN digits against the source. Prefer HTTPS when the source supports it; remove a URL that only repeats the DOI if your style does not need both.
• People are separated with and; organizations have an extra pair of braces, such as author = {{Example Institute}}. Check particles, suffixes, and differing initials against the sources (name examples).
• Capitals that must survive sentence case have protection, such as {NASA} and {Python}. Protect proper names, rather than every word.
• Literal &, %, _, and # in text fields are escaped as \&, \%, \_, and \#. URL and DOI fields handle these characters separately. Mathematical expressions such as $L_p$ keep their mathematical syntax. Braces balance, and accented names remain readable in UTF-8.
• The chosen style prints the information you need. A library's abstract, keywords, or attachment path normally does not appear in the reference list. doi=false or url=false in the style options can hide fields.

Styles and limits

Without preamble.tex, the page uses the starter's numeric style for field advice. It recognizes numeric, author–year, IEEE, APA, MLA, Chicago (including biblatex-chicago), and ACS setups from the style examples. Unknown styles receive general checks with a notice. Field expectations are starting points from the biblatex manual (opens in a new tab), not a claim that every source must have every field. APA adds DOI or URL advice. APA and IEEE add a review of unprotected capitals in English titles (IEEE keeps book titles in title case); MLA, Chicago, and ACS add field suggestions. See the APA package manual (opens in a new tab) and IEEE style source (opens in a new tab) for their sentence-case behavior. Custom styles and field options can change what prints.

This is a partial check, not Biber (the bibliography processor) or a style review. It does not visit links, verify published facts, infer which chapter files your document includes, or decide whether two similar names are the same person. Citation commands hidden in custom commands may be missed. It reads common braced and quoted entries, string macros defined before use, and concatenated values. When an entry is missing a closing brace, the page reports it and checks the following entries on their own. It skips citations inside \verb, \lstinline, and verbatim or listing environments. Inherited fields (crossref or xdata) are reported for review rather than treated as missing. Advanced date notation, custom name formats, and custom data models may need manual review. Files are limited to 5 MB per selection; split larger libraries before checking.

A clean result means these checks found nothing to flag. Follow Check the output yourself for the references in your PDF.

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