I'm currently working on my undergraduate dissertation. I'm working on covering sapces of Riemann surfaces so my supervisor asked me to read the book I mention in the title: "Algébre et Théories Galoisiennes" by Régine and Adrien Douady. The final scope is to prove the following theorem in the book:

Let $ B$ be a Rieamann surface, $v_B $ the category of ramified analytic coverings of $B$ and $e_B $ the category of étale algebras over $M(B)$ (the field of meromorphic functions on $B$). Then the functor $M: X\mapsto M(X) $ from $v_B $ to $e_B $ is an antiequivalence of categories.

The problem is that the suggested literature is in french so it took three times the average time to read a page. Besides, the topic is totally new for me so I'm not making any progress. I'm aware of the fact that probably there is not a translation of that document so what I'm looking for is a text in English which deals with this theorem.

If some of you could suggest some literature I would be very grateful. Thank you all in advance.