“…On the other hand, some studies have considered settings with more than one crane sharing a stack, a similar setting as this paper (see for example, Dorndorf & Schneider, 2010;Gharehgozli, et al, 2015;Li, et al, 2012;Li, et al, 2009;Park, et al, 2010;Stahlbock & Voß, 2010;Ng, 2005;Saanen & Valkengoed, 2005;Choe, et al, 2007;Dell, et al, 2009). In most papers, the problem is formulated as a mixed integer model and minimizing makespan is the main objective (see for example, Gharehgozli et al, 2015;Vis and Carlo, 2010;Briskorn & Angeloudis, 2016;.…”