Marlow Model in fenics

Hey people,

I was suggested to use the Marlow viscoelastic Model for rubber calculations. Until now, I have not been able to find any basic paper of this model or how to implement it in any programming language, but how to realize it in Abaqus, where there are no equations…

Does anyone know the reason or have an idea, where to find something about that?

Thank you very much.
Florian