Perhaps you should try some spelling variations:
"het eerste internationale conferentie festival" » "het eerste international conference festival" (Expand Search), "de eerste internationale conferentie festival" (Expand Search)
"en de internationale heus festival" » "en de internationale des festival" (Expand Search), "en de internationale de festival" (Expand Search), "en de internationale hulp festival" (Expand Search), "en _ international heus festival" (Expand Search), "en de internationale het festival" (Expand Search), "en de internationale wheels festival" (Expand Search), "en de internationale blues festival" (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 eerste internationale conferentie festival") OR ("en de internationale heus festival"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"het eerste internationale conferentie festival\") OR (\"en de internationale heus festival\"))".
• Removing quotes may allow a broader search: (( het eerste internationale conferentie festival ) OR ( en de internationale heus festival )).
• Adding a wildcard symbol may retrieve word variants: (("het eerste internationale conferentie festival") OR ("en de internationale heus festival"))*.