3Ritchie AM. Evaluation of rockfall and its control. Highway Research Record of USA, Record 17, Washington D. C., 1963, 13 -28.
4Peckover FL and Kerr JWG. Treatment and maintenance of rock slopes on transportation routes. Can. Geotech. J, 1977,i4:497 507.
5Piteau DR and Peckover FL. Engineering of rock slopes. Land- slides analysis and control, National academy of Sciences, 1978, 192 - 227.
6Statham I. A simple dynamic model of rockfall: some theoretical principles and field experiments. Int. Colloquium on Physical and Geomechanical Models, ISMES Bergamo, 1979, 237 - 258.
7Bozzolo D and Pamini R. Simulation of rock falls down a valley side. Acta Mechanica, 1986,63 : 113 - 130.
8Dayr W. Case studies of rockfall in soft versus hard rock. Environ- mental and Engineering Geoscience, 1997,3( 1 ) : 133 - 140.