None. There is no silver bullet: http://faculty.salisbury.edu/~xswang/Research/Papers/SERelated/no-silver-bullet.pdf http://faculty.salisbury.edu/~xswang/Rese

None. There is no silver bullet: http://faculty.salisbury.edu/~xswang/Research/Papers/SERelated/no-silver-bullet.pdf http://faculty.salisbury.edu/~xswang/Research/Papers/SERelat...