Lateral torsional buckling of slender concrete girders according to Stiglat

[bizo]

Does anyone have or know the literature where I could find the exact procedure for lateral stability proof of concrete beams according to Stiglat? I found some stuff on web but can't find some tables for beta and k1, k2 & k3 coefficients?

Or does anyone know any other calculation method for this problem and literature?

thnx