A hierarchical algorithm for making sparse matrices sparser. - S. Frank Chang; S. Thomas McCormick (Math. Program., 1992)

The Weighted Sparsity Problem: Complexity and Algorithms. - S. Thomas McCormick; S. Frank Chang (SIAM J. Discret. Math., 1993)

Implementation and computational results for the hierarchical algorithm for making sparse matrices sparser. - S. Frank Chang; S. Thomas McCormick (ACM Trans. Math. Softw., 1993)