I. Kolář: Induced connections and connection morphisms. Proceedings of the ČSSR-GDR-Polish Scientific School on Differential Geometry, Institute of Mathematics of the PAN, Warszawa 1979, 125-134.
 I. Kolář: Connections in 2-fibered manifolds
. Arch. Math. (Brno) XVII (1981), 23 - 30. MR 0672485
 I. Kolář: Fiber parallelism and connections
. Proceedings of Colloquium in West Berlin, Lecture Notes in Mathematics 838 (1981), 165-173. MR 0636278
 J. L. Koszul: Fibre bundles and differential geometry. Tata Institute of Fundamental Research, Bombay 1960.