Subtree and Substar Intersection Numbers. - Yi-Wu Chang; Michael S. Jacobson; Clyde L. Monma; Douglas B. West (Discret. Appl. Math., 1993)

The Bar Visibility Number of a Graph. - Yi-Wu Chang; Joan P. Hutchinson; Michael S. Jacobson; Jenö Lehel; Douglas B. West (SIAM J. Discret. Math., 2004)