1. Aminov, Yu.: The Geometry of Vector Fields. Gordon and Breach Science Publishers, Amsterdam (2000)
2. Apostol, T.: Calculus, Volume II, 2nd edn. Wiley, New York (1969)
3. Beller, D.A., Machon, T., Čopar, S., Sussman, D.M., Alexander, G.P., Kamien, R.K., Mosna, R.: Geometry of the cholesteric phase. Phys. Rev. X 4, 031050 (2014)
4. Bishop, R.L.: There is more than one way to frame a curve. Am. Math. Mon. 82, 246–251 (1975)
5. Bryant, R.L., Chern, S.S., Gardner, R.B., Goldschmidt, H.L., Griffiths, P.A.: Exterior Differential Systems. Springer, New York (1991)