Perhaps you should try some spelling variations:
internationale seminar » international seminar (Expand Search), internationaal seminarie (Expand Search), internationale meeting (Expand Search)
internationale mars » internationale des (Expand Search), internationale dag (Expand Search), internationale de (Expand Search)
de internationale » _ international (Expand Search)
et internationale » en internationale (Expand Search), een internationale (Expand Search), het internationaal (Expand Search)

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( de internationale mars prize ) OR ( et internationale seminar prize ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( de internationale mars prize ) OR ( et internationale seminar prize ))*".