Equation Icon  [ ( ) ] ( ) ( ) |∇-Φ| |∇-Φ|2 |∇-Φ-| a20eff |∇-Φ-|2- ∇. μ a0eff ∇ Φ − s2 μ a0eff + s2 F a2 = 4πG ρ, (27 ) 0 0 0eff