Perhaps you should try some spelling variations:
references collections » reference collections, references collective, references solutions
references collection » reference collection, referenced collections, reference collections
cancer references » cancer recurrence
shear references » shells references, layer references, order references
other references » further references, proper references

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: (( r references collection ) OR ((( shear references collections ) OR ( ((other references) OR (cancer references)) collections )))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( r references collection ) or ((( shear references collections ) or ( ((other references) OR (cancer references)) collections ))))".
• Adding a wildcard symbol may retrieve word variants: (( r references collection ) or ((( shear references collections ) or ( ((other references) OR (cancer references)) collections ))))*.