The recent introduction into Internet of Clase and Periodica bibliographic databasics, is good to carry out a balance and offer a prospective about their development. Reference is made both to their background and main characteristics: geographic and tematic covering, number of records included, selection and obtaining of their information sources, updating and temporary interruption, users' group, as well as access ways and facilities. These databases, produced at Universidad Nacional Autónoma de México, have been offering, for more than twenty years, information found in documents published in about 2,400 journal, issued in Latin America and the Caribbean.
Servicios de información; Databases; Clase; Periodica; Serials; Latin America and the Caribbean; Information services; Internet
