Hiroyuki Okamura Yasuhiro Watanabe Tadashi Dohi Estimating Mixed Software Reliability Models Based on the EM Algorithm. 69-78 2002 conf/isese/2002 ISESE http://doi.ieeecomputersociety.org/10.1109/ISESE.2002.1166927 db/conf/isese/isese2002.html#OkamuraWD02