Perhaps you should try some spelling variations:
"the urban bias sources" » "the urban beams sources", "the urban iras sources", "the urban gas sources", "the urban bus sources"
"the urban stias series" » "the urban atlas series", "the urban studies series", "the urban series series", "the urban alias series", "the urban spatial series"
"the urban soils series" » "the urban soil series", "the urban soils sources", "the urban soils soils", "the urban social series"
"the urban bias series" » "the urban atlas series", "the urban bus series"
"the urban spas series" » "the urban space series", "the urban status series", "the urban atlas series", "the urban spaces series", "the urban sepls series"

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