00584naa#a2200169#i#450# EN\\bibl\4390 20250125165850.6 20201207b2020####ek#y0engy0150####ca RU Nonstrict methods for a posteriori error estimation Conference article/thesis Nizhny Novgorod ANO "Scientific and Research Center for Information in Physics and Technique" 2020 4 с. Conference article/thesis local Математика. 51 Bondarev Aleksandr Alekseev Aleksey srcipt.editorum.ru