I'd like to supply referencies and give table of content in large article. But how should I format the post? Its url looks like http://forum/topic.id/#post-id , so # is already used.
Well assuming you have ID parameters in your article (you just need to add an ID parameter to any HTML attribute... for example, id="yourJumpToPoint"), you can just reference that ID instead of the #post-id. They are unique to the page, not the post, so you wouldn't need to reference the #post-id.
This is of course assuming you are editing directly via HTML.
This is rather difficult for most of users. Maybe one can add special bbcode or, better, improve the forum engine? I know this feature is not a problem in IPB for many years.