An optimal procurement policy for items with an inventory level-dependent demand rate and fixed lifetime. - Hark Hwang; Kyu Hun Hahn (Eur. J. Oper. Res., 2000)

A returns policy for distribution channel coordination of perishable items. - Kyu Hun Hahn; Hark Hwang; Seong Whan Shinn (Eur. J. Oper. Res., 2004)