How to format your references using the Ophthalmologica Extra citation style

This is a short guide how to format citations and the bibliography in a manuscript for Ophthalmologica Extra. For a complete guide how to prepare your manuscript refer to the journal's instructions to authors.

Using reference management software

Typically you don't format your citations and bibliography by hand. The easiest way is to use a reference manager:

PaperpileThe citation style is built in and you can choose it in Settings > Citation Style or Paperpile > Citation Style in Google Docs.
EndNoteFind the style here: output styles overview
Mendeley, Zotero, Papers, and othersThe style is either built in or you can download a CSL file that is supported by most references management programs.
BibTeXBibTeX syles are usually part of a LaTeX template. Check the instructions to authors if the publisher offers a LaTeX template for this journal.

Journal articles

Those examples are references to articles in scholarly journals and how they are supposed to appear in your bibliography.

Not all journals organize their published articles in volumes and issues, so these fields are optional. Some electronic journals do not provide a page range, but instead list an article identifier. In a case like this it's safe to use the article identifier instead of the page range.

A journal article with 1 author
Wu S: State tomography via weak measurements. Sci Rep 2013;3:1193.
A journal article with 2 authors
Wang G, Or D: Trophic interactions induce spatial self-organization of microbial consortia on rough surfaces. Sci Rep 2014;4:6757.
A journal article with 3 authors
Peñalver E, Grimaldi DA, Delclòs X: Early Cretaceous spider web with its prey. Science 2006;312:1761.
A journal article with 7 or more authors
Sinclair RC, Mark MM, Moore SE, Lavis CA, Soldat AS: An electoral butterfly effect. Nature 2000;408:665–666.

Books and book chapters

Here are examples of references for authored and edited books as well as book chapters.

An authored book
Burgess M: Analytical Network and System Administration. Chichester, UK, John Wiley & Sons, Ltd, 2005.
An edited book
Erdmann VA, Poller W, Barciszewski J (eds): RNA Technologies in Cardiovascular Medicine and Research. Berlin, Heidelberg, Springer, 2008.
A chapter in an edited book
Bodo E, Migliorati V: Theoretical Description of Ionic Liquids; in Caminiti R, Gontrani L (eds): The Structure of Ionic Liquids. Cham, Springer International Publishing, 2014, pp 127–148.

Web sites

Sometimes references to web sites should appear directly in the text rather than in the bibliography. Refer to the Instructions to authors for Ophthalmologica Extra.

Blog post
Hamilton K: Genes Can Have Up To 80% Influence On Students’ Academic Performance. IFLScience 2016;


This example shows the general structure used for government reports, technical reports, and scientific reports. If you can't locate the report number then it might be better to cite the report as a book. For reports it is usually not individual people that are credited as authors, but a governmental department or agency like "U. S. Food and Drug Administration" or "National Cancer Institute".

Government report
Government Accountability Office: Aircraft Maintenance: FAA Needs to Follow Through on Plans to Ensure the Safety of Aging Aircraft. Washington, DC, U.S. Government Printing Office, 1993.

Theses and dissertations

Theses including Ph.D. dissertations, Master's theses or Bachelor theses follow the basic format outlined below.

Doctoral dissertation
Walker D: University Research Adminstrators’ Perception of Incivility and the Relationship to Employee Engagement 2017;

News paper articles

Unlike scholarly journals, news papers do not usually have a volume and issue number. Instead, the full date and page number is required for a correct reference.

New York Times article
Robertson C, Walsh MW: Debt Crisis? Bankruptcy Fears? See Jefferson County, Ala. New York Times 2011;A13.

In-text citations

References should be cited in the text by sequential numbers in square brackets:

This sentence cites one reference [1].
This sentence cites two references [1,2].
This sentence cites four references [1–4].

About the journal

Full journal titleOphthalmologica Extra
ISSN (online)2296-1445

Other styles