@article{Lopatatzidis2017IJAR,
title = "Computing lower and upper expected first-passage and return times in imprecise birth–death chains",
journal = "International Journal of Approximate Reasoning ",
volume = "80",
pages = "137 - 173",
year = "2017",
doi = "http://dx.doi.org/10.1016/j.ijar.2016.08.008",
url = "http://www.sciencedirect.com/science/article/pii/S0888613X16301372",
author = “Stavros Lopatatzidis, Jasper De Bock and Gert de Cooman"
}