• [1] E. Cartan, Leçons sur la géométrie des espaces de Riemann, Paris, Gauthier-Villars, 1959.
• [2] H. Hopf and W. Rinow, Ueber den Begriff der vollständigen differentialgeometrischen Fläche, Comment. Math. Helv. 3 (1931), no. 1, 209–225 (German). MR 1509435, http://dx.doi.org/10.1007/BF01601813
• [3] L. Markus, Global structure of ordinary differential equations in the plane, Trans. Amer. Math. Soc. 76 (1954), 127–148. MR 0060657 (15,704a), http://dx.doi.org/10.1090/S0002-9947-1954-0060657-0
• [4] Charles W. Misner and John A. Wheeler, Classical physics as geometry: Gravitation, electromagnetism, unquantized charge, and mass as properties of curved empty space, Ann. Physics 2 (1957), 525–603. MR 0093387 (19,1237i)

Bibliography

[1]

E. Cartan, Leçons sur la géométrie des espaces de Riemann, Paris, Gauthier-Villars, 1959.

[2]

H. Hopf and W. Rinow, Über den Begriff der vollständigen differentialgeometrischen Fläche, Comm. Math. Helv. vol. 3 (1931) pp. 209-225. MR 1509435

[3]

L. Markus, Global structure of ordinary differential equations in the plane, Trans. Amer. Math. Soc. vol. 76 (1954) pp. 127-147. MR 0060657 (15:704a)

[4]

C. W. Misner and J. A. Wheeler, Classical physics as geometry; gravitation, electromagnetism, unquantized charge, and mass as properties of curved empty spaces, Annals of Physics vol. 2 (1957) pp. 525-603. MR 0093387 (19:1237i)