Perhaps you should try some spelling variations:
approximation algorithm » approximation algorithms
optimization algorithm » optimization algorithms, optimisation algorithm, estimation algorithm
one approximation » time approximation, _ approximation, rough approximations
modified staffing » modified caging
modified one » modified male, modified near, modified orca

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "(( modified one approximation algorithm ) OR ( modified staffing optimization algorithm ))~".
• Adding a wildcard symbol may retrieve word variants: (( modified one approximation algorithm ) OR ( modified staffing optimization algorithm ))*.