Perhaps you should try some spelling variations:
"modified objective approximation algorithm" » "modified objective approximation algorithms"
"certified network optimisation algorithm" » "certified network optimization algorithms", "certified network estimation algorithm", "certified network estimation algorithms", "certified network optimization algorithm", "verified network optimisation algorithm"

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: (("certified network optimisation algorithm") OR ("modified objective approximation algorithm"))~.
• Removing quotes may allow a broader search: (( certified network optimisation algorithm ) or ( modified objective approximation algorithm ))~.
• Adding a wildcard symbol may retrieve word variants: (("certified network optimisation algorithm") or ("modified objective approximation algorithm"))*.