Kanesan Muthusamy Shao Chin Sung Milan Vlach Hiroaki Ishii Scheduling with fuzzy delays and fuzzy precedences. 387-395 2003 134 Fuzzy Sets and Systems 3 http://www.sciencedirect.com/science/article/B6V05-45TTSN9-1/2/21cae861965aa45bddae22dd64b65fc9 db/journals/fss/fss134.html#MuthusamySVI03