Srikar and Ghosh (1986) reported an MILP model for this problem; Stafford and
Tseng (1990) also reported; and Rios-Mercado and Barod (1998) gave another article
in this field. Tseng and Stafford (2001) also proposed two other new MILP
models for the SDST flowshop and managed to solve instances of up to nine jobs
and nine machines in about 5 min of CPU time on a Pentium III running at
800 MHz