Bibliographia Gersonideana: Annotated bibliography of primary and secondary sources on this medieval Jewish thinker, compiled by Menachem Kellner.
FOLDOC: Gersonides Levi ben Gershom: Brief entry and recommended reading from this philosophical database.
Gersonides: Article by Tamar Rudovsky from the Stanford Encyclopedia of Philosophy. Provides a bibliography, in addition to discussions of this philosopher's life, work and doctrine of astrological determinism.
Levi ben Gershon: Article on this medieval philosopher and astronomer, from the Jewish Encyclopedia.
Levi ben Gerson: Biographical article with links and bibliography, from the MacTutor History of Mathematics.
Wikipedia: Gersonides: Article from this openly-edited encyclopedia.