Maslov Indices and Monodromy
  We prove that for a Hamiltonian system on a cotangent bundle that is Liouville-integrable and has monodromy the vector of Maslov indices is an eigenvector of the monodromy matrix with eigenvalue 1. As a corollary the resulting restrictions on the monodromy matrix are derived. 
HR Dullin, JM Robbins, H Waalkens, SC Creagh, G Tanner