%0 Journal Article %A F. G. Avkhadiev %T Estimates of Hardy--Rellich constants for polyharmonic operators and their generalizations %J Ufa mathematical journal %D 2017 %P 8-17 %V 9 %N 3 %I mathdoc %U http://geodesic.mathdoc.fr/item/UFA_2017_9_3_a1/ %G en %F UFA_2017_9_3_a1