Delgoshaei, Aidin, Mohd Khairol Ariffin, B. T. Hang Tuah Bin Baharudin, and Zulkiflle Leman. 2014. “A Backward Approach for Maximizing Net Present Value of Multi-Mode Pre-Emptive Resource-Constrained Project Scheduling Problem With Discounted Cash Flows Using Simulated Annealing Algorithm”. International Journal of Industrial Engineering and Management 5 (3):151-58. https://doi.org/10.24867/IJIEM-2014-3-117.