The method for evaluating thermal neutron flux measurements by foils, which was developed by Ritchie and Eldridge, has proven to be a valuable tool for the experimenter. However, there is some difficulty in obtaining the proper definitions and numerical quantities essential for its application. Especially, there developed a need for an easy way to find the function g(γ, τ). Therefore, a compilation was made of all important définitions, exact and approximate relations, and numerical values pertaining to this problem.