Perhaps you should try some spelling variations:
american societies » american society, american cities, american science
robert walter » robert walters, roberts walter, robert walker
robert walt » robert watt, robert wait, robert watts

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: ((robert walt) OR (robert walter)) (american societies).
• Adding a wildcard symbol may retrieve word variants: ((robert walt) or (robert walter)) (american societies)*.