Perhaps you should try some spelling variations:
information agents » information access, information about, information among
using definition » sensing definition, aging definitions, timing definition
information age » information storage
definition from » definitions from, definition file, definition framing
from liberia » from siberia, from nigeria, from liver

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((information agents) OR (information age)) using definition from liberia~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((information agents) OR (information age)) using definition from liberia".
• Adding a wildcard symbol may retrieve word variants: ((information agents) OR (information age)) using definition from liberia*.