1. A Hardy Inequality in Sobolev Spaces;Bourgain,1981
2. Approximation of functions of n variables by quasipolynomials;Brudnyi;Math. USSR–Izv.,1970
3. Yu. Brudnyi, N. Krugljak, A family of approximation spaces. (Russian), in: Studies in the Theory of Functions of Several Real Variables, No. 2, Yaroslav. Gos. Univ., Yaroslavl, 1978, pp. 15–42 (in Russian).
4. Yu. Brudnyi, N. Krugljak, Interpolation Functors and Interpolation Spaces, Vol. I, North-Holland, Amsterdam, 1991.
5. Yu. Brudnyi, V. Salashov, Complex interpolation of Lipschitz spaces. (Russian), in: Qualitative and Approximate Methods for the investigation of Operator Equations, No. 4, Yaroslav. Gos. Unvi., Yaroslavl, 1979, pp. 30–42 (in Russian).