I don't think there is a compact way to cite references in electronic text. The best you can hope for is a target tag somewhere close to your cite. This is already a problem with web pages (even ignoring their transient nature) and leads to cites like "approx 1/3 through page
www.foo.org/... as archived in June 2007 at
www.archive.org/... in the section containing 'thus spake Zarathustra'". Ugly but effective, and always available as a fallback if the page author is so rude as to not supply targets for each paragraph (or at least each chapter).