Equation Icon  (n) 1 ∮ ( ′ ′ (n) (n) ′′) ′ 1 ∫ ′ ′ (n) hαβ = --- G+αβγ δ∇ μ′hγ′δ′ − hγ′δ′∇ μ′G+αβγ δ dS μ + --- G+αβγ δS γ′δ′dV ′. (21.8 ) 4 π∂Ω 4π Ω