Rauch, H. E. (1951). "A Contribution to Differential Geometry in the Large". The Annals of Mathematics. 54 (1): 38–55. doi:10.2307/1969309. JSTOR1969309.
Rauch, H. E. (1951). "A Contribution to Differential Geometry in the Large". The Annals of Mathematics. 54 (1): 38–55. doi:10.2307/1969309. JSTOR1969309.