If you don't like the built-in HTML and/or styling, you should consider the following alternatives:
* modify the CSS (for example, to hide the bullets)
* use an extension, such as asciidoctor-bibliography
What I encourage you not to do is create non-semantic AsciiDoc that mixes content and presentation. We made Asciidoctor extensible so you didn't have to resort to those measures.
> [[[3]]] probably fails because "3" is not a valid id name (allows lower
case letters, digits, periods, hyphens, underscores, but must not start
with a digit).
Cheers,
-Dan