“…Subsequent improvements using B&B [4,17] stimulated development of optimization methods for MWISP [1,2,12,14,16,20,25,28,33,[38][39][40][41]47]. Balas and Xue [3] devised a notable algorithm that extended their previous work [2], using a fast heuristic for the weighted-fractional coloring problem to obtain good upper bounds for B&B.…”