In 1991,Otis Gilley and Gordon Karels,after studying the Giffen problem,proposed a new solution model using an entirely different point of view,now referred to as the Gilley Karels model.

• 九十年代初OtisGiley和GordonKarels在研究Gifen问题时，一反传统做法，从一个全新的角度给出了新的问题求解模型。 简称为Giley－Karels模型。