@misc{misc445653d8, title = {Bounds for optimal coverings}, author = {Moreira, Carlos Gustavo Tamm de Araujo and Kohayakawa, Yoshiharu}, year = {2004}, doi = {10.1016/S0166-218X(03)00372-X}, booktitle = {Brazilian Symposium on Graphs, Algorithms and Combinatorics - GRACO} }