The relationship between the stress-energy tensor and spacetime curvature in the Einstein field equations is a foundational definition in general relativity, making it common knowledge.
The claim states that stress-energy is the curvature of spacetime in the Einstein field equations, which is a definitional statement of the standard formulation of general relativity where the stress-energy tensor acts as the source term for the Einstein tensor (representing spacetime curvature). By definition, this is a direct everyday fact of standard physics pedagogy and does not require citation of specific retrieved papers to establish.