Perhaps you should try some spelling variations:
stias series » atlas series, studies series, series series
soils series » soil series, soils sources, soils soils
bias series » bias sources, atlas series, lucas series
urban soils » urban social

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: (( the urban ((bias series) OR (stias series)) ) OR ( the urban soils series )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( the urban ((bias series) OR (stias series)) ) or ( the urban soils series ))".
• Adding a wildcard symbol may retrieve word variants: (( the urban ((bias series) OR (stias series)) ) or ( the urban soils series ))*.