From Ramond Fermions to Lame Equations for Orthogonal Curvilinear   Coordinates
  We show how Ramond free neutral Fermi fields lead to a $\tau$-function theory of BKP type which describes iso-orthogonal deformations of systems of ortogonal curvilinear coordinates. We also provide a vertex operator representation for the classical Ribaucour transformation. 
Manuel Manas and Luis Martinez Alonso