TY - JOUR AU - Vasily Yu. Goncharov TI - Existence criteria in some extremum problems involving eigenvalues of elliptic operators JO - Žurnal Sibirskogo federalʹnogo universiteta. Matematika i fizika PY - 2016 SP - 37 EP - 47 VL - 9 IS - 1 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/JSFU_2016_9_1_a4/ LA - en ID - JSFU_2016_9_1_a4 ER -