There are some lacks in the documentation.

• the vector bundle stated as "Möbius bundle" is actually no Möbius bundle (the transition function is wrong)
• the frames induced by trivializations are denoted by (psi^*e_i). This is not standard notation and should therefore be explained.
• references added

CC: @egourgoulhon @tscrim

Component: geometry

Keywords: vector-bundles

Author: Michael Jung

Branch/Commit: a8dc34e

Reviewer: Eric Gourgoulhon

Issue created by migration from https://trac.sagemath.org/ticket/28963