1. C. Siniscalchi,The evolution of Slope Stability Analysis, in “Geotecnica”, 1963, No. 4.
2. Taylor,Fundamentals of Soil Mechanics, Wiley, New York; Chapman, London, 1948; Paragraphs 16.17 and 16.18 (pages 441 to 448), from which it is quoted nearly completly.
3. F. Arredi,L'acqua nei mezzi porosi e i suoi effetti meccanici, in “L'Acqua”, 1962, No. 2, March–April.
4. W. Fellenius,Erdstatische Berechnungen mit Reibung und Kohäsion (Adhäsion) und unter Annahme Kreisz ylindrischer Gleitflächen, Berlin, 1927.