Perhaps you should try some spelling variations:
american societies » american society, american cities, american science
robert walker » robert hawker, robertson walker, robert warren
robert walsh » robert walser, robert walt, robert welch

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