1. D. R. Adams, A trace inequality for generalized potentials. Studia Math. 48 (1973), 99–105.
2. O. V. Besov, V. P. Ilin, S. M. Nikolskii, Integral representation of functions and imbedding theorems. (Russian) Izdat. Nauka, Moscow, 1975.
3. B. Bojarski, Pointwise differentiability of weak solutions of elliptic divergence type equations. Bull. Polish Acad. Sci. Math. 33:1–2 (1985), 1–6.
4. B. Bojarski, Sharp maximal operator of fractional order and Sobolev imbedding inequalities. ibid. 33:1–2 (1985), 7–16.
5. B. Bojarski, Remarks on Markov's inequalities and some properties of polynomials. ibid. 33:7–8 (1985), 355–365.