I don't know if it is better to ask here or on MSE, if that's the case I can post the question there. I would need a simple version of the martingale central limit theorem. And, by simple, I mean the simple statement provided on Wikipedia: https://en.wikipedia.org/wiki/Martingale_central_limit_theorem.
The problem is, I can only find references proving more general results with somewhat dense notations. I would need a simple reference proving exactly the simple case of the Wikipedia page, but so far I have not managed to find anything.