Preemptive multi-skilled resource constrained project scheduling problem with hard/soft interval due datesHamidreza Maghsoudlou, Behrouz Afshar-Nadjafi and Seyed Taghi Akhavan NiakiRAIRO-Oper. Res., 53 5 (2019) 1877-1898DOI: https://doi.org/10.1051/ro/2018103
