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

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