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

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