All styles consist of two parts.  The first is the in-text citation, which gives enough information for the reader to find the reference in the second part, the list of references at the end of the document. 

Referencing styles fall into three main groups:

1. Name-date
• In-text citations consists of the author(s) name and date of publication
• References listed in alphabetical order of authors surname in reference list
2. Consecutive numbering
• In-text citations consists of a number
• A new number is used each time a reference is cited
• References listed in numerial order in reference list
3. Recurrent numbering
• In-text citations consists of a number
• If a reference is cited more than once the number is re-used
• References listed in numerical order in reference list

If you are uncertain which referencing style you should be using contact your department or ask your tutor for advice. 

The university's guide to academic good practice discusses citing and referencing and how to use them to avoid plagiarism.

This is how a book (Carroll, 2009), book chapter (Shishkin et al., 2000), journal article (Nakajima & Schoch, 2011) and conference paper (Zajic, 2006) look in the Harvard name-date style.

References

Carroll, R.L., 2009. The rise of amphibians: 365 million years of evolution, Baltimore: The John Hopkins University Press.

This is how a book¹, book chapter², journal article³ and conference paper⁴ look in the citation style of the journal Nature, a recurrent numbering style.

1. Carroll, R.L. The rise of amphibians: 365 million years of evolution. 360 (The John Hopkins University Press: Baltimore, 2009).

2. Shishkin, M.A., Novikov, I.V. & Gubin, Y.M. Permian and Triassic temnospondyls from Russia. The Age of Dinosaurs in Russia and Mongolia 35-59 (2000).

3. Nakajima, Y. & Schoch, R.R. The first temnospondyl amphibian from Japan. Journal of Vertebrate Paleontology 31, 1154-1157 (2011).

4. Zajic, J. The main fish communities of the limnic Permian and Carboniferous basins of the Czech Republic. 7th Paleontological Conference 33-34, 99-101 (2006).

If you're having an issue with a reference management tool, please email us at the address below. Please give us as much information as you can, particularly:

• Your Department/Faculty or subject area
• The reference management tool or software you are using (RefWorks, EndNote, Mendeley, Zotero etc.)
• The operating system of the machine you are using (Windows 10, Mac OS X Mountain Lion etc.)
• The browser you are using (Chrome, Firefox, Internet Explorer, Safari etc.)
• The word processor you are using (Word, Pages etc.)

Contact us at reference-management@bodleian.ox.ac.uk.