Preprint Series # 124 Izumiya, Shyuichi Completely integrable holonomic systems of first order differential equations. (1991);
Preprint Series # 126 Izumiya, Shyuichi Completely integrable holonomic systems of first order differential equations. (1991);
Preprint Series # 100 Izumiya, S. Geometric singularities for HamiltonāJacobi equation. (1991);
Preprint Series # 101 Izumiya, S. Legendrian singularities and first order differential equations. (1991);