Referral Centres:

A referral centre is some sort of "information desk" for the scientific and technical community which does not provide enquirers directly with the information they need, but suggests sources (organizations or individuals) likely to satisfy the clients. The Science and Technology Division of the Library of Congress maintains one of the most active referral centres - the National Referral Center. An efficient referral centre maintains an exhaustive inventory of significant information sources and also publishes directories of such sources.