[1] R. S. Mishra: Structures in a differentiable manifold. INSA Scientific report series No. 3, New Delhi, 1978.
[3] A. G. Walker:
Connexions for parallel distributions in the large I, II. Quart. J. Math. Oxford (2), 6, (1955), 301-308 and 9, (1958), 221-231.
MR 0087160
[4] T. J. Willmore:
Connexion for a system of parallel distributions. Quart. J. Math. Oxford (2), 7, (1956), 209-276.
MR 0097832
[5] K. Yano:
Diflferential geometry on complex and almost complex spaces. Pergamon Press, (1965).
MR 0187181