Philippe Baptiste Jacques Carlier Alexander Kononov Maurice Queyranne Sergey Sevastyanov Maxim Sviridenko Integrality Property in Preemptive Parallel Machine Scheduling. 38-46 2009 CSR http://dx.doi.org/10.1007/978-3-642-03351-3_6 conf/csr/2009 db/conf/csr/csr2009.html#BaptisteCKQSS09