The increasing number of information available at libraries and the necessity to find a mechanism to look for information at several libraries at the same time promoted to the creation of the Z39.50 protocol. Since it has been launched, many Z39.50 clients have been developed, but most of them only have access to a reduced number of libraries catalogues and are focused on the point of view of the library users. We present a Z39.50 client that adds new features focused on the point of view of researchers and publishing houses. With our proposal the user can add the catalogue of any library whenever he wants in order to facilitate the process of looking for the desired information. Our Z39.50 client shows as well the situation of the closest libraries where the results of the information searched by the user is located. Finally, we have compared our Z39.50 client with the existing ones.