Perhaps you should try some spelling variations:
"modified notion approximation algorithms" » "modified network approximation algorithms", "modified time approximation algorithms", "modified one approximation algorithms"
"verified network estimation algorithm" » "verified network optimization algorithm", "certified network estimation algorithm", "defined network estimation algorithm"

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 notion approximation algorithms\") OR (\"verified network estimation algorithm\"))~".
• Removing quotes may allow a broader search: (( modified notion approximation algorithms ) OR ( verified network estimation algorithm ))~.
• Adding a wildcard symbol may retrieve word variants: (("modified notion approximation algorithms") OR ("verified network estimation algorithm"))*.