Mahnken, Rolf, and E Stein. “The Identification of Parameters for Visco-Plastic Models via Finite-Element Methods and Gradient Methods.”https://doi.org/10.1088/0965-0393/2/3a/013__Modelling and Simulation in Materials Science and Engineering 2, no. 3A (2002): 597–616.https://doi.org/10.1088/0965-0393/2/3a/013 .

Mahnken, Rolf, and Erwin Stein. “Parameter Identification for Finite Deformation Elasto-Plasticity in Principal Directions.”https://doi.org/10.1016/s0045-7825(97)00008-x__Computer Methods in Applied Mechanics and Engineering 147, no. 1–2 (2002): 17–39.https://doi.org/10.1016/s0045-7825(97)00008-x .