Tien Van Do 0001 Dénes Papp Ram Chakka János Sztrik Jinting Wang M/M/1 retrial queue with working vacations and negative customer arrivals. 52-65 2014 6 Int. J. Adv. Intell. Paradigms 1 https://doi.org/10.1504/IJAIP.2014.059586 db/journals/ijaip/ijaip6.html#DoPCSW14