%0 Journal Article %T An Efficient Algorithm to Solve the Conditional Covering Problem on Trapezoid Graphs %A Akul Rana %A Anita Pal %A Madhumangal Pal %J ISRN Discrete Mathematics %D 2011 %I Hindawi Publishing Corporation %R 10.5402/2011/213084 %U http://dx.doi.org/10.5402/2011/213084