  Six works have been attributed to Thomas of Erfurt. In addition to the aforementioned grammatical treatise, whose full title is Tractatus de modis significandi seu Grammatica speculativa (ed. Bursill-Hall  1972),[5]  there are four short expositiones, or literal commentaries: on Porphyry's Isagoge, Aristotle's Categories, Aristotle's De interpretatione, and the anonymous Liber sex principiorum (Book of Six Principles). Finally, there is a very brief work of mnemonic verses for teaching grammar to schoolboys, Commentarius in carmen ‘Fundamentum puerorum’ (ed. Gansiniec 1960), although its editor believes that it is actually an anonymous abridgement of De modis significandi. In any case, Thomas's entire reputation derives from De modis significandi, which remains his only work to have been studied in any detail.