Perhaps you should try some spelling variations:
"the natural histories series" » "the natural historical series", "the natural history series", "the natural histories stories", "the natural histories theories"
"the oral histories series" » "the oral histories stories", "the oral histories theories", "the oral historical series", "the oral history series", "the moral historical series"

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: "((\"the natural histories series\") OR (\"the oral histories series\"))".
• Removing quotes may allow a broader search: (( the natural histories series ) OR ( the oral histories series )).
• Adding a wildcard symbol may retrieve word variants: (("the natural histories series") OR ("the oral histories series"))*.