TY  - JOUR
TI  - Matrix geometric method for Markovian queueing model with breakdown, backup server, working vacation and customer impatience
AU  - P., I.
AU  - K., K.
JO  - Sigma Journal of Engineering and Natural Sciences
PY  - 2026
VL  - 44
SP  - 3231
EP  - 3245
DO  - 10.14744/sigma.2026.2156
ER  -