In 1987 he also won a bronze medal at the World Judo Championships.
Houkes won gold in the men's under 60-kilo class at the 2007 World Judo Championships.
He also won a bronze medal in the 1983 World Judo Championships.
He won a bronze medal at the open category of the 2005 World Judo Championships.
He went on to win a bronze medal in the 2011 World Judo Championships.
She received a gold medal at the 1997 World Judo Championships.
A year earlier he won a bronze medal at the 1979 World Judo Championships.
He won two gold medals and a silver medal at the World Judo Championships.
She won silver at the 1995 World Judo Championships.
He participated in 2005 World Judo Championships, but ended at fifth.