Institution: | (1) Institute of Physics, Czechosl. Acad. Sci., Na Slovance 2, 180 40, Czechoslovakia;(2) Mathematical Institute, Czechosl. Acad. Sci., itná 25, 115 67 Praha 1, Czechoslovakia;(3) Faculty of Civil Engineering, Czech Technical University, Thákurova 7, 166 29 Praha 6, Czechoslovakia |