Bynagle, Philosophy, a Guide to the Reference Literature, Main, B 72 .B97 1986. Annotates leading reference works in the field, general bibliographies, encyclopedias, dictionaries, indexes to periodical literature, specialized bibliographies on schools, periods, branches, countries, and individual philosophers. Also concordances and indexes to works of individual philosophers.
DeGeorge, Guide to Philosophical Bibliography and Research, Main Z 7125 .D4. Similar to the above work in purpose. Selectively annotated with many entries per page. For the medieval period see especially pages 19-20 and 32-41.