TY - JOUR AU - V. V. Smelov TI - Approximation of piecewise-smooth functions by the eigenelements of two Sturm--Liouville problems JO - Doklady Akademii Nauk PY - 1980 SP - 573 EP - 577 VL - 250 IS - 3 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/DAN_1980_250_3_a15/ LA - ru ID - DAN_1980_250_3_a15 ER -