1. An estimate of the probability that a diffusion process hits a set of positive measure (with N. V. Krylov), Soviet Math. Dokl. vol 20 (1979), no. 2, 253-255. | pdf

2. Nonlinear elliptic equations of second order, Lecture notes. Dipartimento di Matematica Applicata "G. Sansone", Universita degli studi di Firenze, 1991, 52 p. | pdf

3. Linear Elliptic Equations of Second Order, 1994, 35 p. | pdf

4. On the boundary value problems for fully nonlinear elliptic equations of second order. CMA Research Report MRR 049-94, 1994, 34 p. (corrected version). | pdf

5. Growth Theorems and Harnack Inequality for Second Order Parabolic Equations (with Elisa Ferretti). In: "Contemporary Mathematics", Volume 277, 2001, pp. 87-112. | pdf

6. Non-divergence Elliptic Equations of Second Order with Unbounded Drift. AMS Translations (2) 29 (2010), 211-232. | pdf

7. On Second Order Elliptic and Parabolic Equations of Mixed Type (with Gong Chen), preprint, June 2013. | pdf

---