1. Lei , L. , and Wang , T. J. “ A Proof on the NP-completeness of the Hoist Scheduling Problems ,” GSM Working Paper #89–16 , Rutgers University ( August 1989 ).
2. The Minimum Common-Cycle Algorithm for Cyclic Scheduling of Two Material Handling Hoists with Time Window Constraints
3. Shapiro , G. W. “ Hoist scheduling for a PCB Electroplating Facility ,” Unpublished M.S. Thesis , North Carolina State University ( 1985 ) .