Perhaps you should try some spelling variations:
internationaal verdrag » internationale dag (Expand Search)
internationale seminar » international seminar (Expand Search), internationaal seminarie (Expand Search), internationale meeting (Expand Search)
eerste internationale » de internationale (Expand Search)
het internationaal » _ international (Expand Search), de internationale (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: (( het internationaal verdrag prize ) OR ( eerste internationale seminar prize ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( het internationaal verdrag prize ) OR ( eerste internationale seminar prize ))".
• Adding a wildcard symbol may retrieve word variants: (( het internationaal verdrag prize ) OR ( eerste internationale seminar prize ))*.