Ullrich, C. (2013). Integrated machine scheduling and vehicle routing with time windows. European Journal Of Operational Research, 227(1), 152-165. Elsevier BV. doi:10.1016/j.ejor.2012.11.049.
Ullrich, C. (2012). Supply chain scheduling: makespan reduction potential. International Journal Of Logistics, 15(5), 323-336. Informa UK Limited. doi:10.1080/13675567.2012.742045.