INEQUALITIES FOR VALUES OF DIFFERENTIAL-OPERATORS ON ALGEBRAIC POLYNOMIALS ON A SPHERE Статья ZHIDKOV G.V. Differential Equations. Том 17. 1981. С. 329-336
THE STABILIZATION AND LIMITING AMPLITUDE OF THE CAUCHY-PROBLEM SOLUTION FOR INHOMOGENEOUS SOBOLEV SYSTEMS Статья MASLENNIKOVA V.N., PAL P.K. Doklady Akademii nauk SSSR. Mezhdunarodnaya Kniga, Moscow, Russian Federation. Том 259. 1981. С. 1297-1302