Talvez debería tentar con algunhas variantes ortográficas:
formation problem » location problem, population problem, formation process
surface extension » surfaces extension, surface tension, surface expression
problem surface » problem space, problem trace, problems face
array string » array strong, arrays strings, array sharing
array using » arrays using

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: formation problem surface extension ((((array string) OR (array using))) OR (array format))~.
• Adding a wildcard symbol may retrieve word variants: formation problem surface extension ((((array string) or (array using))) or (array format))*.