Conjugacy classes of involutive automorphisms of the $C_{\ell}^{(1)}$   affine Kac-Moody algebras
  The conjugacy classes of the involutive automorphisms of the affine Kac-Moody algebras \Cli\ for $\ell\geq 2$ are determined using the matrix formulation of automorphisms of an affine Kac-Moody algebra. 
S. P. Clarke and J. F. Cornwell