@inproceedings{UP97,
   author = {I. Ulidowski and I.C.C. Phillips},
   title = {Formats of Ordered {SOS} Rules with Silent Actions},
   booktitle = {TAPSOFT '97: Theory and Practice of Software Development,
CAAP/FASE, Lille, April 1997},
   series = {Lecture Notes in Computer Science},
   publisher = {Springer-Verlag},
   volume = 1214,
   pages = {297-308},
   year = 1997
}