1. The distribution of the ratio, in a single normal sample, of range to standard deviation;David;Biometrika,1954
2. Appunti di Idrologia: Introduzione alle Elaborazione Statistiche;Maione,1974
3. Multivariate Statistical Methods;Morrison,1976
4. Eutrophication of Waters;Vollenweider,1982
5. Mathematical Ecology;Pielou,1977