Ladies and Gentlemen. Good afternoon.

I recently learned o XForms, and I am interested to know more about it.

I am particularly interested in creating "API" interfaces based on
XForms, and to create XSLT stylesheets that would equally realize these
interfaces.

I would also appreciate available examples of any kind.

You might want to look at Declarative Amsterdam papers and videos, like
https://www.youtube.com/watch?v=BxftX_Wi44U. Steven Pemberton has
provided several talks and tutorial about XForms.