B. Ross Barmish, Christopher V. Hollot, Frank J. Kraus, and
Roberto Tempo, "Extreme point results for robust stabilization of
interval plants with first order compensators", <I> IEEE
Transactions on Automatic Control</I>, 1992, Vol. 37, No. 6, pp.
707-714.
<P>

(See Barmish Tempo 1990). In this paper, it is shown that under a
certain condition, a controller stabilizes the system for <I> all</I>
possible combinations of parameters from given intervals iff it
stabilizes 16 (sometimes even 8) combinations. 
This result is illustrated by a controller for an experimental oblique
wing aircraft.