%0 Journal Article %A G. N. Yakovlev %T Traces of functions in the space $W_p^l$ on piecewise smooth surfaces %J Sbornik. Mathematics %D 1967 %P 481-497 %V 3 %N 4 %I mathdoc %U http://geodesic.mathdoc.fr/item/SM_1967_3_4_a3/ %G en %F SM_1967_3_4_a3