accessible and which are only destined for a limited group
of users, e.g., for the staff of certain organizations.
Looking at the whole scene of automated information
storage and retrieval, we may conclude that much effort
worldwide has been invested in various kinds of databases.
But, as noted in the Introduction, there is no single
database for the whole field of aerospace. In each
individual case of an on-line search it is up to the user to
select the most appropriate database or combination of
databases. One important advancement is that nowadays
the best known hosts offer the possibility of cluster
searching, i.e., when starting the retrieval procedure, you
may combine some appropriate databases and search
them as if they were one single database.
We hope that this paper will help users to make the best
choice of databases for an on-line search.
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