|
[1] William M. Boothby. An Introduction to Differentiable Manifolds and Rieman- nian Geometry. ACADEMIC PRESS,INC, Orlando,Florida, second edition, 1986. [2] J.Milnor. On manifolds homeomorphic to the 7-sphere. Annals of Mathematics, 64:399{405, 1956. [3] James R. Munkres. Elements of Algebraic Topology. rst edition.
|