 Hans Ziegler extended the Melan-Prager non-equilibrium theory of materials to the non-isothermal case.Gyarmati (1967/1970) gives a systematic presentation, and extends Onsager's principle of least dissipation of energy, to give a more symmetric form known as Gyarmati's principle.Gyarmati (1967/1970) cites 11 papers or books authored or co-authored by Prigogine.