$LS_{\lowercase {r}}$-valued Gauss maps and spacelike surfaces of   revolution in $\mathbb R_1^4$
  To study spacelike surfaces in the Lorentz-Minkowski space $\Bbb R^{4}_1,$ we construct a pair of maps whose values are in the lightcone, called $\mathfrak l_r^{\pm} $-Gauss maps. We can use these maps to study umbilical spacelike surfaces and find parametrizations of spacelike surfaces of revolution of hyperbolic and eliptic types in some particular cases. 
Dang Van Cuong
math.DG