<P> An abstracting service is a service that provides abstracts of publications, often on a subject or group of related subjects, usually on a subscription basis . An indexing service is a service that assigns descriptors and other kinds of access points to documents . The word indexing service is today mostly used for computer programs, but may also cover services providing back - of - the - book indexes, journal indexes, and related kinds of indexes . An indexing and abstracting service is a service that provides shortening or summarizing of documents and assigning of descriptors for referencing documents . </P> <P> The product is often an abstracts journal or a bibliographic index, which may be a subject bibliography or a bibliographic database . </P>

Describe the difference between abstracting and indexing service
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