Published in Apex (Brussels), in 1998, in volume 13, pages 77-79

Published in Apex (Brussels), in 1998, in volume 13, pages 95-109

Published in Apex (Brussels), in 1998, in volume 13, pages 111-125

Published in Apex (Brussels), in 1998, in volume 13, pages 127-130

Published in Apex (Brussels), in 1998, in volume 13, pages 131-153

Published in Apex (Brussels), in 1998, in volume 13, pages 155-160

Published in Apex (Brussels), in 1998, in volume 13, pages 177-179

Published in Apex (Brussels), in 1998, in volume 13, issue 1-2, pages 63-75