Como funciona el protocolo OAI-PMH en la recuperación de información

In this article it is tried to describe the operation of protocol OAI - PMH (Open Archives Initiative - Protocol Metadata Harvesting), from the interoperability between the supplier of data and the supplier of services by means of the example of a information necessity of a user of a Centre Specialized in Lawyer, is there where it started this request of information to a supplier of services that used the protocol to communicate with a supplier of data, which will resort to repository to look for the information required by the initial user