Perhaps you should try some spelling variations:
"het internationaal seminarie prize" » "het international seminar prize" (Expand Search), "het international solidarity prize" (Expand Search), "_ international seminarie prize" (Expand Search), "de internationale seminarie prize" (Expand Search)
"en internationale mars prize" » "en internationale des prize" (Expand Search), "en internationale dag prize" (Expand Search), "en internationale de prize" (Expand Search), "de internationale mars prize" (Expand Search), "_ international mars prize" (Expand Search), "eerste internationale mars prize" (Expand Search)

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"en internationale mars prize\") OR (\"het internationaal seminarie prize\"))~".
• Removing quotes may allow a broader search: (( en internationale mars prize ) OR ( het internationaal seminarie prize ))~.
• Adding a wildcard symbol may retrieve word variants: (("en internationale mars prize") OR ("het internationaal seminarie prize"))*.