Hello, I am new to UMAT for Abaqus and need to write UMAT for hyperelastic material. For plasticity theory, there are many books explaining computational aspects and even commenting about writing plasticity model in Abaqus. I did not find any such text for nonlinear elasticity. Can someone suggest good books (this is what I am mainly interested) or references for writing UMAT hyperelastic models? I know continuum mechanics and good books, but interested in computational aspects.