Simply drag and drop the file/folder into a note with pressed 'Alt' key, than a reference/link is created in the note instead of a copy.
Found this method (here), tested it on my windows system and thougt WOW! 
So I left a 
for the source post and repeat it here to spread it to everyone again...even if everybody except me knew it already 
Useful tip, thanks!
Interesting that this behaviour adds newline chars (2 before, 3 after) around the created reference. Adding such newlines is identical to when a file is Attached, whether by drag-drop or menu (Edit -> Attach File).
Would be time-saving to be able to disable/customize the addition of newlines. I am deleting them every time I attach/insert actual files or file references.
I agree the new lines addition when dragging/dropping files or references should be optional