1. A. V. Ivanov, “On the structure of quasilinear elliptic equations of the second order,” Zap. Nauch. Sem. Leningr. Otd. Mat. Inst., Akad. Nauk SSSR,19, 79–94 (1970).
2. A. V. Ivanov, “Local estimates of the first derivatives of the solutions of second-order quasilinear elliptic equations and their applications to Liouville-type theorems,” Zap. Nauchn. Sem. Leningr. Otd. Mat. Inst., Akad. Nauk SSSR,30, 40–50 (1972).
3. O. A. Ladyzhenskaya and N. N. Ural'tseva, Linear and Quasilinear Elliptic Equations, Academic Press, New York (1968).
4. A. V. Pogorelov, The Multidimensional Minkowski Problem [in Russian], Nauka, Moscow (1975).
5. W. V. Wahl, “Einige neue innere Abschätzungen für nichtlineare elliptische Gleichungen und Systeme,” Math. Z.,134, 119–128 (1973).