Anthony Cárdenas under the supervision of Nitti,
included references only to manuscripts copied before 1501 or to incunabula,
i.e., printed editions prior to 1501. These were taken initially from the
first edition of the Bibliografía de la literatura española
of José Simón Díaz, whose volume on medieval literature
was published in 1953, and supplemented with references to the pre-1501
Escorial manuscripts taken from the Blessed Julián Zarco Cuevas'
Catálogo de los manuscritos castellanos de la Real Biblioteca de
El Escorial (1924-29), the first catalogue of medieval Spanish manuscripts
that merits the name, as well as the introductions to the various editions
of medieval Spanish works and other materials in the Seminary.
The sources of the second edition (1977) included the nine published
volumes of the Inventario general de manuscritos de la Biblioteca Nacional
(the only ones which had appeared to thatcentralized at Berkeley,
although the editorial team continued to collaborate closely with Madison's
Medieval Spanish Seminary. In 1987, thanks to a grant from IBM, BOOST was
ported from a main frame flat file database into Revelation (later Advanced
Revelation, from Revelation Technologies), a high-end, DOS-based relational
database management system.

In 1993 the DOS version of PhiloBiblon, with three of its component
bibliographies (BETA, BITAGAP, BITECA), was published on CD-ROM as part of
disk 0 of ADMYTE (Archivo Digital de Manuscritos y Textos Españoles),
produced by Micronet, S.A. (Madrid), with the support of the Biblioteca Nacional
and the Sociedad Estatal del Quinto Centenario and under the direction of
Francisco Marcos Marín in company with Faulhaber and Gómez Moreno.
A new, revised, and expanded edition of the DOS version was published on
CD-ROM in 1999 by The Bancroft Library. It is now out