Perhaps you should try some spelling variations:
"modified coverage approximation algorithms" » "modified average approximation algorithms", "modified _verage approximation algorithms", "modified dfverage approximation algorithms", "modified orcaverage approximation algorithms"
"modified co evolution algorithm" » "modified co solution algorithm", "modified co evolutionary algorithm", "modified co convolution algorithms", "modified _ evolution algorithm", "modified df evolution algorithm", "modified orca evolution algorithm"

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