[phenixbb] n_gaussian tables?

Hi Phenixers, I gather that the wk1995 and it1992 scattering tables come from Waasmaier & Kirfe (1995), Acta Cryst. A51, 416-431 and the International Tables Vol C 1992 respectively. Can someone please tell me from where the n_gaussian scattering tables are derived? With thanks, a++