If you are using another researcher's dataset, it's important to cite it to give that producer credit. Citing data also simplifies access to data for re-use.
Elements of Data Citations:
Data Creator
Title of Dataset
Year of Publication
Publisher (usually the data repository where the dataset is housed)
Edition or Version
Access Information (URL or other persistent identifier)
A recommended format is:
Creator (PublicationYear). Title. Publisher. Identifier
or, if version and type of resource are available:
Creator (PublicationYear). Title. Version. Publisher. ResourceType. Identifier
Data Citation Index, from Web of Science, provides a citation for each dataset indexed in the product.