. . . . "http://eilv.cie.co.at/term/1245"^^ . . . "Spherical illuminance is equal to quotient of the total luminous flux \\(\\Phi_v\\) incident on a small sphere by the cross section area of that sphere."^^ . "Illuminance"@en . "\\(E_v,0 = \\int_{4\\pi sr}{L_v}{d\\Omega}\\), where \\(d\\Omega\\) is the solid angle of each elementary beam passing through the given point and \\(L_v\\) is its luminance at that point in the direction of the beam."^^ . .