1. [B1]Yu. A. Brudnyi (1963):Generalization of a theorem of A. F. Timan, Dokl Akad. Nauk SSSR,148:1237?1240. (English translation (1963): Soviet Math. Dokl.,4: 244?247.)
2. [B2]Yu. A. Brudnyi (1964):On a theorem of local best approximation. Kazan. Gos. Univ. U?en. Zap.,124:43?49.
3. [B3]Yu. A. Brudnyi (1970):Approximation of functions of n variables by quasipolynomials. Izv. Akad. Nauk SSSR Ser. Mat.,34:564?583. (English translation (1970): Math. USSR-Izv.,4:568?585.).
4. [B4]Yu. A. Brudnyi (1971):Spaces defined by local approximations. Trudy Moscow Mat. Obshch.,24:69?132. (English translation (1971): Moscow Math. Soc.,24:73?139.)
5. [DeL]R. A. DeVore, D. Leviatan (1993):Convex polynomial approximation in L p (0