@incollection {MR1151217,
    AUTHOR = {Kawski, Matthias},
     TITLE = {Practical computation of accessibility, controllability and
              nilpotent approximations},
 BOOKTITLE = {Algebraic computing in control ({P}aris, 1991)},
    SERIES = {Lecture Notes in Control and Inform. Sci.},
    VOLUME = {165},
     PAGES = {334--345},
 PUBLISHER = {Springer},
   ADDRESS = {Berlin},
      YEAR = {1991},
   MRCLASS = {93B40},
  MRNUMBER = {MR1151217},
}