EXACT CONSTANTS IN AN INEQUALITY FOR THE MODULUS OF THE DERIVATIVE, AND BEST APPROXIMATIONS OF A DIFFERENTIATION FUNCTIONAL AT A POINT OF A SEGMENT Статья Burenkov V.I., Gusakov V.A. Doklady Akademii Nauk. Том 356. 1997. С. 295-296
ON MIXED PROBLEMS FOR THE KORTEWEG-DE VRIES EQUATION WITH IRREGULAR BOUNDARY DATA Статья Faminskiĭ A.V. Doklady Akademii Nauk. Том 366. 1999. С. 28-29