Cheng, T.C. Edwin and Shakhlevich, Natalia (1999) Proportionate flow shop with controllable processing times. Journal of Scheduling, 2 (6). pp. 253-265. ISSN 1094-6136 (Print), 1099-1425 (Online) (doi:10.1002/(SICI)1099-1425(199911/12)2:6<253::AID-JOS30>3.0.CO;2-R)

Shakhlevich, Natalia, Hoogeveen, Han and Pinedo, Michael (1998) Minimizing total weighted completion time in a proportionate flow shop. Journal of Scheduling, 1 (3). pp. 157-168. ISSN 1094-6136 (Print), 1099-1425 (Online) (doi:10.1002/(SICI)1099-1425(1998100)1:3<157::AID-JOS12>3.0.CO;2-Y)