In 1992 , he and his family moved to Bellevue , Washington .
After retiring from the University of Michigan in 1986 , Hilbert and his family moved to Brussels , Belgium , where Hilbert was director of the European Office of the National Sanitation Foundation .
In 1992 , Hilbert and Hilbert 's family moved to Bellevue , Washington .
After retiring from the University of Michigan in 1986 , Hilbert and his family moved to Brussels , Belgium , where Hilbert was director of the European Office of the National Sanitation Foundation .