Perhaps you should try some spelling variations:
american colonization » americans colonization
african association » american association, european association
prison association » american association

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((((african association) OR (prison association))) OR (american colonization)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((african association) OR (prison association))) or (american colonization))".
• Adding a wildcard symbol may retrieve word variants: ((((african association) OR (prison association))) or (american colonization))*.