Columbia subject headings:
Electronic publishing.
Image files--Abstracting and indexing.
Indexing.
Information storage and retrieval systems.
Text files--Abstracting and indexing.
Harvard subject headings:
Image files--Abstracting and indexing.
Text files--Abstracting and indexing.
Princeton subject headings:
Electronic publishing--Abstracting and indexing.
Image processing--Abstracting and indexing.
Indexing.