Return Type

This selection determines what type of references will be returned.

If "Abstracts" is selected, all abstracts selected by the query will be returned.
If "References" is selected, all abstracts of articles are returned which are references in the articles returned by the first query.
If "Citations" is selected, all abstracts of articles are returned which cite articles returned by the first query.

The numerical fields for selection determine for which papers the references/citations are to be found.