Andrzej Chydzinski On the Remaining Service Time upon Reaching a Given Level in M/G/1 Queues. 71-80 2004 47 Queueing Syst. 1-2 http://dx.doi.org/10.1023/B:QUES.0000032801.90131.04 db/journals/questa/questa47.html#Chydzinski04