# Source for a coordinate-based formula for Gauss from Riemann

• Geometry

## Main Question or Discussion Point

I need a citeable source that gives the formula for the Gaussian curvature at a single point of an intrinsically defined Riemannian or Semi-Riemannian manifold given the intrinsic metric tensor and/or Riemann tensor.

I've got sources for this already, but I'm not "allowed" to use them for this, I need a professionally published journal/textbook source for a citation.