Letter
A Letter reports an important novel research study, but is less substantial than an Article. Letters typically occupy four printed journal pages. The text is limited to 1,500 words, excluding the introductory paragraph, Methods, references and figure legends. Letters should have no more than 3-5 display items (figures and/or tables). As a guideline, Letters allow up to 30 references.

This format begins with a title of, at most, 15 words, followed by an introductory paragraph (not abstract) of approximately 150 words, summarizing the background, rationale, main results (introduced by "Here we show" or some equivalent phrase) and implications of the study. This paragraph should be referenced, as in Nature style, and should be considered part of the main text, so that any subsequent introductory material avoids too much redundancy with the introductory paragraph.