This theory was proposed in 1966 to go beyond BCS theory of superconductivity and it provides predictions of upper critical field (Hc2) in type-II superconductors . The theory predicts the upper critical field (Hc2) at 0 K from Tc and the slope of Hc2 at Tc.
eg Referred : re MgB2
References
Werthamer–Helfand–Hohenberg theory Wikipedia(Text) CC BY-SA