[1] Gilbarg D., Trudinger P., Ellipticheskie differentsialnye uravneniya s chastnymi proizvodnymi vtorogo poryadka, Nauka, M., 1989 | MR | Zbl

[2] Ilin V. A., “O ryadakh Fure po fundamentalnym sistemam funktsii operatora Beltrami”, Differents. uravneniya, 5:11 (1969), 1940–1978 | MR | Zbl

[3] Ilin V. A., “Nekotorye svoistva regulyarnogo resheniya uravneniya Gelmgoltsa v ploskoi oblasti”, Mat. zametki, 15:6 (1974), 885–890 | Zbl

[4] Ilin V. A., Moiseev E. I., “Ob odnom obobschenii formuly srednego znacheniya dlya regulyarnogo resheniya uravneniya Shredingera”, IPM AN SSSR, 1977, 157–166 | MR | Zbl

[5] Ilin V. A., Moiseev E. I., “Formula srednego znacheniya dlya prisoedinennykh funktsii operatora Laplasa”, Differents. uravneniya, 17:10 (1981), 1908–1910 | MR | Zbl

[6] Moiseev E. I., “Formula srednego dlya sobstvennykh funktsii ellipticheskogo samosopryazhennogo operatora vtorogo poryadka”, DAN SSSR, 197:3 (1971), 524–525 | MR | Zbl

[7] Moiseev E. I., “Asimptoticheskaya formula srednego znacheniya dlya regulyarnogo resheniya differentsialnogo uravneniya”, Differents. uravneniya, 16:5 (1980), 827–844 | MR | Zbl

[8] Khelgason S., Differentsialnaya geometriya i simmetricheskie prostranstva, Mir, M., 1964

[9] Ion F., Ploskie volny i sfericheskie srednie, Izd-vo inostr. lit., M., 1958

[10] Bitsadze A. V., Nakhushev A. M., “K teorii uravnenii smeshannogo tipa v mnogomernykh oblastyakh”, Differents. uravneniya, 10:12 (1974), 2184–2191 | Zbl

[11] Gelfand I. M., Shilov G. E., Obobschennye funktsii i deistviya nad nimi, Fizmatgiz, M., 1958 | Zbl

[12] Khermander L., Analiz lineinykh differentsialnykh operatorov s chastnymi proizvodnymi, v 4 t., v. 1, Mir, M., 1986 | MR

[13] Ivanov L. A., Polovinkin I. P., “O nekotorykh svoistvakh operatora Beltrami v rimanovoi metrike”, Dokl. RAN, 365:3 (1999), 306–309 | MR

[14] Meshkov V. Z., Polovinkin I. P., “K svoistvam reshenii lineinykh uravnenii v chastnykh proizvodnykh”, Chernozemnyi almanakh nauchnykh issledovanii. Ser. Fundam. mat., 1(5) (2007), 3–11