1. Romanov A. S., “On the traces of Sobolev functions on the boundary of a cusp with a Hölder singularity,” Siberian Math. J., 48, No. 1, 176–184 (2007).
2. Romanov A. S., “Traces of functions of generalized Sobolev classes,” Siberian Math. J., 48, No. 4, 848–866 (2007).
3. Vasil’chik M. Yu. and Gol’dshteĭn V. M., “Solvability of the third boundary-value problem in a domain with a peak,” Math. Notes, 78, No. 3, 424–426 (2005).
4. Bojarski B. and Hajłasz P., “Pointwise inequalities for Sobolev functions and some applications,” Studia Math., 106, No. 1, 77–92 (1993).
5. Hajłasz P., “Sobolev spaces on an arbitrary metric spaces,” Potential Anal., 5, No. 4, 403–415 (1996).