@articleMahnken_Stein_2002, title=The identification of parameters for visco-plastic models via finite-element methods and gradient methods, volume=2, DOI=10.1088/0965-0393/2/3a/013, number=3A, journal=Modelling and Simulation in Materials Science and Engineering, publisher=IOP Publishing, author=Mahnken, Rolf and Stein, E, year=2002, pages=597–616 
LibreCat: /record/45432
DOI: 10.1088/0965-0393/2/3a/013

@articleMahnken_Stein_2002, title=Parameter identification for finite deformation elasto-plasticity in principal directions, volume=147, DOI=10.1016/s0045-7825(97)00008-x, number=1–2, journal=Computer Methods in Applied Mechanics and Engineering, publisher=Elsevier BV, author=Mahnken, Rolf and Stein, Erwin, year=2002, pages=17–39 
LibreCat: /record/45428
DOI: 10.1016/s0045-7825(97)00008-x