Thanks, Ihor.

I would like to customize the name of the heading. I think it should be customized this function: "Org Bibtex Headline Format Function".

Is there a guide to do this?

I can see the default is:

#[257 "\300
\236A\207"
      [:title]
      3 "\n\n(fn ENTRY)"]

But I don't know how to customize it.

ChatGPT says:

"Unless you are an advanced Emacs Lisp developer and have a specific need to work with byte-compiled code, you generally don't need to interact with or modify this representation directly. Instead, you can work with the function using its regular name and definition."

And ChatGPT offers me this alternative, which doesn't seem to work (BTW, I am not able to install asoc.el):

#+begin_src emacs-lisp
(defun my-org-bibtex-headline-format (entry)
  "Custom function to generate the headline text for org-bibtex-write."
  (let* ((title (cdr (assoc :title entry)))
         (author (cdr (assoc :author entry))))
    (concat "Mi encabezado personalizado: " title " - " author)))

(setq org-bibtex-headline-format #'my-org-bibtex-headline-format)
#+end_src

Best regards