The text is limited to 2,500 words, including the introductory paragraph, but excluding online Methods, references and figure legends. Letters should have no more than 5 display items (figures and/or tables).
Letters are not divided by headings, except for the online Methods heading. They may be accompanied by supplementary information, Letters are peer reviewed.
Note that Correspondence pieces are not technical comments on peer-reviewed research papers which would be considered Matters Arising.
Matters Arising are exceptionally interesting and timely scientific comments and clarifications on original research papers published in .
These comments should ideally be based on knowledge contemporaneous with the original paper, rather than subsequent scientific developments.
For detailed information on how to submit a Matters Arising, please follow instructions here. They may be linked to articles in , or they may focus on papers of exceptional significance that are published elsewhere.
Titles for Correspondences are supplied by the editors.
Correspondence may be peer-reviewed at the editors’ discretion.
The Results and online Methods should be divided by topical subheadings.
As a guideline, Articles allow up to 70 references. They may be accompanied by supplementary information. A Letter reports an important novel research result, but is less substantial than an Article.