Using existing data can be a means to save time and money. However, some thought is required before reusing data.
Read the data license or end user agreement:
Data citation refers to the practice of referencing data to acknowledge their original source. This is done in much the same way as more traditional resources like books and journal articles.
Citing data is important because it:
Standards for data citation vary across the disciplines. DataCite recommends including the following elements:
Irino, T; Tada, R (2009): Chemical and mineral compositions of sediments from ODP Site 127‐797. Geological Institute, University of Tokyo. http://dx.doi.org/10.1594/PANGAEA.726855
Standards for citing data are not uniformly agreed upon and clear directions in style manuals are few. Where no specific guidance is provided, follow the general format for the style you are using. See A Description of Data Citation Instructions in Style Guides (Purdue University), a comparison of common referencing style manuals.
EndNote software (versions X4 and above) has a template for the reference type 'dataset'. If you are using software that does not include this type of reference, you may be able to create a custom template. Consult the software's manual for more information.
Standards for data citation vary across the disciplines. The Digital Curation Centre provides more information on data citation in their guide How to Cite Datasets and Link to Publications.