1. C. Riquier, Les systemes d'equations aux derivees partielles, Gauthier-Villars, Paris, 1910.
2. S. P. Finikov, Cartan's Method of Exterior Forms in Differential Geometry. The Theory of Consistency of Systems of Total and Partial Differential Equations [in Russian], M.-L., Gostekhizdat, 1948.
3. V. P. Palamodov, “Differential operators in the class of convergent power series and the Weierstrass preparation theorem,” Funkts. Anal. Prilozhen., 2, No.3, 58–69 (1968).
4. A. G. Khovanskii and S. P. Chulkov, “The Hilbert polynomial for systems of linear partial differential equations with analytic coefficients,” submitted to Izv. Ross. Akad. Nauk Ser. Mat.
5. A. G. Khovanskii and S. P. Chulkov, “Hilbert and Hilbert-Samuel polynomils and partial differential equations”, Mat. Zametki, 77, No.1, 141–151 (2005).