Sentence:  Most papers make use of the effective stress based on the Huber-Mises-Hencky (<WSD>HMH</WSD>) hypothesis, and consider either isotropic hardening (P. Perzyna [8]) or mixed isotropic-kinematic hardening (J.L. Chaboche [1]). 
Meaning of the word marked with <WSD> tags:  (dot=,) an alternative name for the von Mises yield criterion