“…This point was emphasized by Noll [42,43], who called a formulation of continuum mechanics on the body B as intrinsic 1 and by Rougée [49,50] who refers to it as an intrinsic Lagrangian framework, whereas a formulation on a reference configuration is denominated as a standard Lagrangian approach. Intrinsic formulations nowadays use modern tools in differential geometry [35,32,15,33,55]. In this direction, we insist on the fundamental role played by the manifold of all the Riemannian metrics on the body -introduced in solids mechanics by Rougée [49,51,52] and Fiala [18,19,20] -in the formulation of hyper-elasticity (see section 3).…”