Reference Style (pnas-citation)

When to trigger

• References are in author–date (APA/Harvard) or another journal's style and must become PNAS style.
• The reference list is not ordered by citation appearance.
• Author lists are truncated with "et al." in the bibliography.
• In-text citations are not numeric.

PNAS citation mechanics

• Numbered, in order of appearance in the text, as numbers in parentheses: (1), (2, 3), (4–6).
• A single numbered reference list, numbered consecutively in the order references first appear in the text.
• The reference list gives full author lists (PNAS does not truncate to "et al." in the bibliography for typical author counts — confirm any cap for very long lists).
• Journal titles abbreviated (standard ISO/CASSI abbreviations); include volume, page or article number, and year.
• Each reference includes the article title.

This is PNAS's own numbered format. It resembles Science in being numbered-by-appearance, but follow the PNAS reference template for punctuation, ordering of elements, and abbreviation conventions — do not assume Science's exact formatting.

Reference formats (shape — confirm details in current PNAS guidelines)

• Journal article: 1. A. B. Author, C. D. Author, E. F. Author, Article title. J. Abbrev. Volume, page–page (Year).
• Book: 2. A. B. Author, Book Title (Publisher, ed. X, Year).
• Book chapter: 3. A. B. Author, Chapter title in Book Title, C. D. Editor, Ed. (Publisher, Year), pp. xx–yy.
• Dataset: 4. A. B. Author, Dataset title. Repository. Accession/DOI. Deposited DD Month Year.
• Preprint: 5. A. B. Author, Title. Repository [Preprint] (Year). DOI/identifier (accessed DD Month Year).

Initials precede surnames; article titles in sentence case; journal abbreviated. Use a reference-manager PNAS style file to enforce this mechanically, then do a manual pass.

Common conversion fixes

Worked conversion (author-date → PNAS numbered)

Source (APA, in text and list):

"Recent work (Smith & Lee, 2021; Okafor et al., 2022) shows …" Smith, J., & Lee, K. (2021). Title of the article. Journal Name, 12(3), 45–58.

PNAS:

"Recent work (1, 2) shows …" — where (1) is the first to appear in the text. 1. J. Smith, K. Lee, Title of the article. J. Name 12, 45–58 (2021).

Note the changes: in-text becomes sequential numbers in appearance order; initials lead surnames; the article title is kept; the journal is abbreviated and italic-by-convention; volume is given without the issue number; full author list (no "et al." in the bibliography).

Tooling

• Use Zotero/EndNote with the PNAS CSL/style; do a final manual pass on abbreviations and author-list completeness (managers often truncate).
• Verify every in-text number resolves and the list has no gaps/duplicates; renumber after any reordering of the text.

Output format

【Style detected】 author-date / other → PNAS numbered
【Numbering】 by appearance? single numbered list? yes/no
【Author lists】 full (not et al.) in biblio? yes/no
【Journal abbreviations】 applied? yes/no
【Element shapes】 article/book/chapter/dataset/preprint correct?
【Unresolved/duplicate refs】 [...]
【Next】 pnas-submission

Anti-patterns

• Do not leave author–date citations anywhere in a PNAS manuscript.
• Do not alphabetize the reference list — order is by appearance.
• Do not truncate author lists with "et al." in the bibliography.
• Do not assume Science's exact reference formatting — use the PNAS template.