There's currently no automated/easy way for cross referencing, but it's definitely planned for a future version. If you want to export to LaTeX, you can use the LaTeX referencing tags like \ref{} in Ulysses directly.
Thank you for your answer. I am not well acquainted with Latex (but it is planned in future developments!) so I will try via scripting, trying to use Ul bookmarks.
I found a trick to create a sort of cross reference, setting another Style that I use as tag for relevant o recurring topics. It is not the better way, but it seems to work.