Talvez debería tentar con algunhas variantes ortográficas:
communication operators » communication operator, communication operations, telecommunications operators
operators series » operator series, operations series, operators fourier
series dimension » series dimensions, regimes dimension, series diffusion
great spaces » great sales, great races, great speeches
green spaces » green space, open spaces
area spaces » area species, arena space, shared spaces

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: communication operators series dimension ((area spaces) or (((great spaces) or (green spaces))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: communication operators series dimension ((area spaces) OR (((great spaces) OR (green spaces)))).
• Adding a wildcard symbol may retrieve word variants: communication operators series dimension ((area spaces) or (((great spaces) or (green spaces))))*.