@unpublished{GeiselhartGielenLazaretal.2013,
  author  = {Roman Geiselhart and Rob H. Gielen and Mircea Lazar and Fabian R. Wirth},
  title   = {An Alternative Converse Lyapunov Theorem for Discrete-Time Systems},
  institution = {Institut f{\"u}r Mathematik},
  year    = {2013},
}