The Duh-Henderson (Ref. 1) (1996) Bridge function retains the Duh Haymet bridge function for γ ∗ ≥ 0 {\displaystyle \gamma ^{*}\geq 0} , and for γ ∗ ≤ 0 {\displaystyle \gamma ^{*}\leq 0} (Eq. 17)