doi          = "10.1109/32.256850",
 doi          = "10.1007/3-540-60472-3\_1",
 doi          = "10.1145/963778.963782",
 doi          = "10.1016/0169-7552(89)90078-0",
 doi          = "10.1109/FMCAD.2009.5351139",
 doi          = "10.1145/571637.571640",
 doi          = "10.1007/BF01843566",
 doi          = "10.1109/ACSD.2010.26",
 doi          = "10.1007/s10009-008-0083-0",
 doi          = "10.1007/3-540-48153-2\_12",
 doi          = "10.4230/LIPIcs.FSTTCS.2011.399",
 doi          = " 10.1145/1755913.1755950",
 doi          = "10.1007/s10703-009-0084-y",
 doi          = "10.1137/0217058",
 doi          = "10.1016/0022-0000(81)90039-8",
 doi          = "10.1007/s10009-004-0146-9",
 doi          = "10.1145/1658357.1658358",
 doi          = "10.1007/BF00289237",
 doi          = "10.1145/1095810.1095817",
 doi          = "10.1145/75277.75293",
 doi          = "10.1007/BFb0035790",
 doi          = "10.1109/2.58235",
 doi          = "10.1007/3-540-55092-5\_13",
 doi          = "10.1007/978-3-540-71410-1\_10",
 doi          = "10.1007/3-540-58715-2\_121",