Perhaps you should try some spelling variations:
"resourcesssssssssssssssssssssssssssss selection functions" » "resourcesssssssssssssssssssssssssssss detection functions" (Expand Search)
"sources selection function" » "sources detection function" (Expand Search)

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("resourcesssssssssssssssssssssssssssss selection functions") OR ("sources selection function"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"resourcesssssssssssssssssssssssssssss selection functions\") OR (\"sources selection function\"))*".
• Removing quotes may allow a broader search: (( resourcesssssssssssssssssssssssssssss selection functions ) OR ( sources selection function ))*.