Edit 24.02.2019. I would like to draw the attention of those who might be interested, to my own attempt to solve this problem. This is chapter 1 in my unfinished course of undergraduate mathematics. This text is designed for my students, that is why it is in Russian, unfortunately. My problem is that I am not an expert in this field and because of that I have to spend too much time on working with the details. And I actually do not have this time, I do this sporadically. This problem with Gödel's completeness theorems (theorems 1.1.22 and 1.1.23 in the text, separately for theories with finite and infinite systems of axioms) is now the only blank spot, if it were resolved, the textbook could be considered finished (I already asked this question at MO before, it is here). The best solution for me would be if someone published an article with accurate proof of these statements in their “highly formalized form” as they are presented in my text, so that I could just refer to his article. (But I must say that a part of the problem is that Gödel's theorem for a theory with an infinite system of axioms is even not accurately formulated in my text, since I was trying to avoid the standard trick of "embedding the given first order theory into arithmetics". I believe it can be replaced by an equivalent trick of "embedding into set theory", but the details are not well written in my text, because I don't see how to "translate this".) So if somebody could give an advise or a reference I would appreciate this very much.
