A summary of formulas for the apparent linearity in the denaturation free energy curves (mapp) and the corresponding preferential binding parameter differences (ΔΓ23) for different models of protein denaturation. See text for an explanation of the symbols. We have used the fact that m3 = ρ3/φ1 for the Local-bulk model (140) and for the Exchange 2 model. N33’ is the derivative of N33 with respect to cosolvent concentration