@CONFERENCE{TCR95,
  author = {Tsiotras, P. and Corless, M. and Rotea, M.},
  title = {An {${\cal L}_2$} Disturbance Attenuation Approach to
	 the Nonlinear Benchmark Problem},
  booktitle = {American Control Conference},
  year = {1995},
  pages = {4352--4356},
  note = {Seattle, WA}
}