Have a look indeed! Most of Aleixandre's letters to Prieto are stored in Prieto's online archive, but almost all of them are uncategorized within said archive... Have this one, i feel like it's a nice example of Aleixandre's handwriting. If you want any more, you should be able to see a couple of arrows to move forward-back, and if the text next to it says "Aleixandre", it'll probably be a letter from him!