S. Poznanski published some valuable specimens of Aaron's work; and, following a suggestion of Harkavy, he threw new light on the author and some other works of his: namely, the Kitab al-Kafi, a commentary on the Pentateuch, often quoted by Karaite writers, and a lexicographical work bearing the title "Sharḥ Alalfaẓ," a part of which is extant in the British Museum.