B. Awbi, M. Shillor and M. Sofonea,

We consider quasistatic evolution of a viscoelastic body which is in
bilateral frictional contact with a rigid foundation. We derive two variational
formulations for the problem: the primal formulation in terms of the
displacements and the dual formulation in terms of the stress field. We
prove the existence of a unique solution to each one and establish the
equivalence between the two variational formulations. We also prove the
continuous dependence of the solution on the friction yield limit.