TY  - JOUR
TI  - Spectra and pseudospectra of the direct sum operators
AU  - ISMAILOV, Z.I.
AU  - IPEK AL, P.
JO  - Sigma Journal of Engineering and Natural Sciences
PY  - 2020
VL  - 38
SP  - 1251
EP  - 1259
DO  - 
ER  -