An abstract is a short, descriptive summary of a work, whether it is a book, journal article, or dissertation. The purpose of an abstract is to provide the reader with a quick understanding of what the work is about. Catalogs and databases often rely on abstracts to improve the ability search and index literature.
You can find examples of abstracts as you browse articles in the following journals:
Many databases and indexes will also provide abstracts of literature that they carry. Try searching immigration and browse the results to see examples:
Additional resources: